There may seem to be no cause for defective or abnormal eggs but usually one of the following reasons are the culprit. Incidences of egg deformities, blood in the eggs, meat particles in eggs, rough shells, soft shelled, cloudy, double shelled or rough shells is much higher in hens who live under stressful conditions.
Conditions which cause defective chicken eggs are:
Conditions which cause defective chicken eggs are:
- Stress induced oviposition (egg in wrong position inside the hen).
- Deep litter
- Moving hens from pens to cages
- Rough handling
- Holding or picking up the wrong way
- Vitamin deficiencies
- Vaccination during production
- Viral diseases such as, bronchitis, egg drop syndrome, and Newcastle disease
- Roundworm
- Foreign material
Causes of eggs with ridges, sunburst appearance, lop sided eggs, soft shelled or double shells are:
When the eggs have ridges, coloring has a sunburst look to it, are lop sided, have soft shells or double shells this is caused by eggs colliding with one another while still inside the hen's shell gland region of her oviduct.
"Occasionally, a hen lays an egg without a shell. A shell-less egg feels like a water balloon. The shell membranes form around the yolk and egg white, but the egg somehow bypasses the shell-forming mechanism, and the shell is not completely deposited. The occurrence of the occasional shell-less egg is not necessarily an indication of health problems. If the incidence increases, however, a nutrition problem, primarily a deficiency of calcium, phosphorus, and/or vitamin D, may exist. If the condition persists, a veterinarian should examine the hen. Infectious bronchitis and egg drop syndrome also have been known to cause an increase in shell-less eggs" (Dr. Jacquie Jacob, University of Kentucky).
Causes of Misshaped and Discolored Eggs:
Collision is caused when an ovum (yolk) is released to soon. Necropsy (autopsy aka dissection) examinations have shown two full size eggs in the gland pouch. When the second egg comes in contact with the first egg it puts pressure on it which causes the natural pattern of mineralization to be disrupted. The first egg will develop a white band with a chalky like appearance while the second egg is flattened on it's surface causing a slab-sided or lop sided egg. "Eggs with abnormal shapes do not fit well into a typical egg carton or are more likely to break during transport, so they are removed during egg inspection and are not normally sold in stores. Hatching eggs also should have the typical egg shape. With many abnormally shaped eggs, it is not clear which is the large end, and eggs should be incubated large end up. Also, such eggs may not properly fit in the egg trays" (Dr. Jacquie Jacob, University of Kentucky).
Causes of Rough Feeling Egg Shells:
Ridges, pimpled or rough feeling shells, are eggs that have stayed in the shell gland too long.
Thin spots in egg shell or ridges:
"Other problems can occur when an egg’s shell is developing. The most obvious relates to shell texture. Occasionally, the shell becomes damaged while the egg is in the shell gland and is repaired before the hen lays the egg. This repair results in what is known as a body check (see Figure 6). Occasionally, thin spots in the shell or ridges form. These shells are weaker than those of normal eggs, so eggs with thin spots are removed during inspection of table eggs and should not be used as hatching eggs" (Dr. Jacquie Jacob, University of Kentucky).
Causes of Blood Spots in Eggs:
Are caused when a follicle vessel (a group of cells which contain a cavity or sac) along the stigma ruptures while the ovum is being released (A. Gregorio Rosales. Mercks. 2018). A follicular stigma is a spot on the surface of the ovary where the vesicular ovarian follicle will rupture and permit passage of the ovum (2).
"Blood spots are normally found on or around the yolk. The main cause of a blood spot is a small break in one of the tiny blood vessels around the yolk that occurs when the yolk is ovulated. High levels of hen activity during the time of ovulation can increase the incidence of blood spots" (Dr. Jacquie Jacob, University of Kentucky).
Causes of Meat Spots in Eggs:
Are caused when a follicle membrane or residual albumen (the main protein found in the white of an egg) from the previous day is incorporated into the developing egg. "Meat spots are usually brown in color and are more often associated with the egg white. They form when small pieces of the wall of the oviduct are sloughed off while the developing egg is passing through. In commercial operations, eggs with blood spots and meat spots typically are identified during candling and removed (see Figure 5). It is rare, therefore, to find eggs with these irregularities in grocery stores. The incidence of blood spots is higher in brown-shelled eggs, and identifying blood spots when candling eggs with darker-colored shells is difficult" (Dr. Jacquie Jacob, University of Kentucky).
Small eggs with no yolk or defective shells:
"Small eggs with no yolk form around a nidus of material (residual albumen) in the magnum of the oviduct. Small eggs with reduced albumen and eggs with defective shells may be the result of damage to the epithelium of the magnum or shell gland" (A. Gregorio Rosales. Mercks. 2018).
"It is rare, but not impossible, for a young hen to produce an egg with no yolk at all. Yolk-less eggs (sometimes referred to as pullet eggs) are usually formed when a bit of tissue is sloughed off the ovary or oviduct. The tissue stimulates the secreting glands of the different parts of the oviduct and a yolk-less egg results" (Dr. Jacquie Jacob, University of Kentucky).
Mottling (Pale yolk or blotches on the yolk):
"If the vitelline membrane surrounding the yolk becomes damaged, pale spots or blotches develop on the yolk. This irregularity is referred to as mottling. Although the appearance of the yolk has changed, there is no effect on the egg’s nutritional value and typically the mottling is not noticed by consumers. A high incidence of yolk mottling, however, adversely affects consumer acceptance. The use of cottonseed meal (which contains gossypol) and sorghum (which contains tannin) in the diet can increase the incidence of mottling. A calcium-deficient diet also has this effect" (Dr. Jacquie Jacob, University of Kentucky).
Double yolked eggs:
Occasionally, a hen produces double-yolked eggs. This phenomenon can be related to hen-age, but genetic factors also are involved. Young hens sometimes release two yolks from the ovary in quick succession. Double-yolked eggs are typically larger in size than single-yolked eggs. Double-yolked eggs are not suitable for hatching as they typically have inadequate nutrients and space available for two chicks to fully develop and hatch. It has happened, but it is rare (Dr. Jacquie Jacob, University of Kentucky).
Egg within an egg:
"Even rarer is an egg within an egg. This occurs when an egg nearly ready to be laid reverses direction, moves up the oviduct and encounters another egg in the process of forming. A new layer of albumen, new membranes, and a new shell form around the first egg, resulting in an egg inside an egg. Such eggs are so rare that no one knows exactly why they happen (Dr. Jacquie Jacob, University of Kentucky)..
See more below.
When the eggs have ridges, coloring has a sunburst look to it, are lop sided, have soft shells or double shells this is caused by eggs colliding with one another while still inside the hen's shell gland region of her oviduct.
"Occasionally, a hen lays an egg without a shell. A shell-less egg feels like a water balloon. The shell membranes form around the yolk and egg white, but the egg somehow bypasses the shell-forming mechanism, and the shell is not completely deposited. The occurrence of the occasional shell-less egg is not necessarily an indication of health problems. If the incidence increases, however, a nutrition problem, primarily a deficiency of calcium, phosphorus, and/or vitamin D, may exist. If the condition persists, a veterinarian should examine the hen. Infectious bronchitis and egg drop syndrome also have been known to cause an increase in shell-less eggs" (Dr. Jacquie Jacob, University of Kentucky).
Causes of Misshaped and Discolored Eggs:
Collision is caused when an ovum (yolk) is released to soon. Necropsy (autopsy aka dissection) examinations have shown two full size eggs in the gland pouch. When the second egg comes in contact with the first egg it puts pressure on it which causes the natural pattern of mineralization to be disrupted. The first egg will develop a white band with a chalky like appearance while the second egg is flattened on it's surface causing a slab-sided or lop sided egg. "Eggs with abnormal shapes do not fit well into a typical egg carton or are more likely to break during transport, so they are removed during egg inspection and are not normally sold in stores. Hatching eggs also should have the typical egg shape. With many abnormally shaped eggs, it is not clear which is the large end, and eggs should be incubated large end up. Also, such eggs may not properly fit in the egg trays" (Dr. Jacquie Jacob, University of Kentucky).
Causes of Rough Feeling Egg Shells:
Ridges, pimpled or rough feeling shells, are eggs that have stayed in the shell gland too long.
Thin spots in egg shell or ridges:
"Other problems can occur when an egg’s shell is developing. The most obvious relates to shell texture. Occasionally, the shell becomes damaged while the egg is in the shell gland and is repaired before the hen lays the egg. This repair results in what is known as a body check (see Figure 6). Occasionally, thin spots in the shell or ridges form. These shells are weaker than those of normal eggs, so eggs with thin spots are removed during inspection of table eggs and should not be used as hatching eggs" (Dr. Jacquie Jacob, University of Kentucky).
Causes of Blood Spots in Eggs:
Are caused when a follicle vessel (a group of cells which contain a cavity or sac) along the stigma ruptures while the ovum is being released (A. Gregorio Rosales. Mercks. 2018). A follicular stigma is a spot on the surface of the ovary where the vesicular ovarian follicle will rupture and permit passage of the ovum (2).
"Blood spots are normally found on or around the yolk. The main cause of a blood spot is a small break in one of the tiny blood vessels around the yolk that occurs when the yolk is ovulated. High levels of hen activity during the time of ovulation can increase the incidence of blood spots" (Dr. Jacquie Jacob, University of Kentucky).
Causes of Meat Spots in Eggs:
Are caused when a follicle membrane or residual albumen (the main protein found in the white of an egg) from the previous day is incorporated into the developing egg. "Meat spots are usually brown in color and are more often associated with the egg white. They form when small pieces of the wall of the oviduct are sloughed off while the developing egg is passing through. In commercial operations, eggs with blood spots and meat spots typically are identified during candling and removed (see Figure 5). It is rare, therefore, to find eggs with these irregularities in grocery stores. The incidence of blood spots is higher in brown-shelled eggs, and identifying blood spots when candling eggs with darker-colored shells is difficult" (Dr. Jacquie Jacob, University of Kentucky).
Small eggs with no yolk or defective shells:
"Small eggs with no yolk form around a nidus of material (residual albumen) in the magnum of the oviduct. Small eggs with reduced albumen and eggs with defective shells may be the result of damage to the epithelium of the magnum or shell gland" (A. Gregorio Rosales. Mercks. 2018).
"It is rare, but not impossible, for a young hen to produce an egg with no yolk at all. Yolk-less eggs (sometimes referred to as pullet eggs) are usually formed when a bit of tissue is sloughed off the ovary or oviduct. The tissue stimulates the secreting glands of the different parts of the oviduct and a yolk-less egg results" (Dr. Jacquie Jacob, University of Kentucky).
Mottling (Pale yolk or blotches on the yolk):
"If the vitelline membrane surrounding the yolk becomes damaged, pale spots or blotches develop on the yolk. This irregularity is referred to as mottling. Although the appearance of the yolk has changed, there is no effect on the egg’s nutritional value and typically the mottling is not noticed by consumers. A high incidence of yolk mottling, however, adversely affects consumer acceptance. The use of cottonseed meal (which contains gossypol) and sorghum (which contains tannin) in the diet can increase the incidence of mottling. A calcium-deficient diet also has this effect" (Dr. Jacquie Jacob, University of Kentucky).
Double yolked eggs:
Occasionally, a hen produces double-yolked eggs. This phenomenon can be related to hen-age, but genetic factors also are involved. Young hens sometimes release two yolks from the ovary in quick succession. Double-yolked eggs are typically larger in size than single-yolked eggs. Double-yolked eggs are not suitable for hatching as they typically have inadequate nutrients and space available for two chicks to fully develop and hatch. It has happened, but it is rare (Dr. Jacquie Jacob, University of Kentucky).
Egg within an egg:
"Even rarer is an egg within an egg. This occurs when an egg nearly ready to be laid reverses direction, moves up the oviduct and encounters another egg in the process of forming. A new layer of albumen, new membranes, and a new shell form around the first egg, resulting in an egg inside an egg. Such eggs are so rare that no one knows exactly why they happen (Dr. Jacquie Jacob, University of Kentucky)..
See more below.
Causes of Abnormal Egg Shells:
Research on brown egg laying hens suggest that hens who under stress and live in deep litter or that have been moved from pens to cages, tend to have more abnormal eggs and lay less eggs than hens who do not. Eggs from stressed hens are of lower quality and have more incidences of soft shelled eggs, bulging eggs, misshapen eggs, eggs coated with a layer of amorphous calcium,(also referred to dusted, white banded, chalky) and pink eggs. “Disturbance to flocks on deep litter resulted in an increase in the proportion of eggs laid with abnormal shells on the following day, not only in the flocks directly affected but also in an adjacent flock” (C.M. Sherwin, M.A.F. Nasr, E. Gale, M. Petek, K. Stafford, M. Turp, G.C. Coles. 2013).
Research on brown egg laying hens suggest that hens who under stress and live in deep litter or that have been moved from pens to cages, tend to have more abnormal eggs and lay less eggs than hens who do not. Eggs from stressed hens are of lower quality and have more incidences of soft shelled eggs, bulging eggs, misshapen eggs, eggs coated with a layer of amorphous calcium,(also referred to dusted, white banded, chalky) and pink eggs. “Disturbance to flocks on deep litter resulted in an increase in the proportion of eggs laid with abnormal shells on the following day, not only in the flocks directly affected but also in an adjacent flock” (C.M. Sherwin, M.A.F. Nasr, E. Gale, M. Petek, K. Stafford, M. Turp, G.C. Coles. 2013).
More Egg Related Topics (Click links to view) |
References:
A. Gregorio Rosales. "Defective or Abnormal Eggs in Poultry - Poultry - Merck Veterinary Manual." Merck Veterinary Manual. n.d. Web. 26 Jan. 2018. <https://www.merckvetmanual.com/poultry/disorders-of-the-reproductive-system/defective-or-abnormal-eggs-in-poultry>
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
C.M. Sherwin, M.A.F. Nasr, E. Gale, M. Petek, K. Stafford, M. Turp, G.C. Coles. (2013) Retrieved on April 1, 2018 from Prevalence of nematode infection and faecal egg counts in free-range laying hens: relations to housing and husbandry. British Poultry Science 54:1, pages 12-23. https://www.tandfonline.com/doi/abs/10.1080/00071668.2012.757577
Dr. K.C. Sheppard, I.J.H. Duncan. (2011) Retrieved on April 1, 2018 from Feeding motivation on the incidence of floor eggs and extraneously calcified eggs laid by broiler breeder hens. British Poultry Science 52:1, pages 20-29. https://www.tandfonline.com/doi/abs/10.1080/00071668.2010.550600
S.E. Solomon. (2010) The eggshell: strength, structure and function. Retrieved on April 1, 2018 from British Poultry Science 51:sup1, pages 52-59. https://www.tandfonline.com/doi/abs/10.1080/00071668.2010.497296
Dr C.M. Sherwin, G.J. Richards, C.J. Nicol. (2010) Retrieved on April 1, 2018 from Comparison of the welfare of layer hens in 4 housing systems in the UK. British Poultry Science 51:4, pages 488-499. https://www.tandfonline.com/doi/abs/10.1080/00071668.2010.502518
V. Guesdon, A.M.H. Ahmed, S. Mallet, J.M. Faure, Dr Y. Nys. (2006). Retrieved on April 1, 2018 from Effects of beak trimming and cage design on laying hen performance and egg quality. British Poultry Science 47:1, pages 1-12. https://www.tandfonline.com/doi/abs/10.1080/00071660500468124
Frankie D. Jackson, Alberto Garrido, James G. Schmitt, Luis M. Chiappe, Lowell Dingus, David B. Loope. (2004). Retrieved on April 1, 2018 from Abnormal, multilayered titanosaur (Dinosauria: Sauropoda) eggs from in situ clutches at the Auca Mahuevo locality, Neuquen Province, Argentina. Journal of Vertebrate Paleontology 24:4, pages 913-922. https://www.tandfonline.com/doi/abs/10.1671/0272-4634%282004%29024%5B0913%3AAMTDSE%5D2.0.CO%3B2
Frankie D. Jackson, David J. Varricchio. (2003). Retrieved on April 1, 2018 from Abnormal, multilayered eggshell in birds: implications for dinosaur reproductive anatomy. Journal of Vertebrate Paleontology 23:3, pages 699-702. https://www.tandfonline.com/doi/abs/10.1671/A1092
M. Reynard, C. J. Savory. (1999). Retrieved on April 1, 2018 from Stress-induced oviposition delays in laying hens: Duration and consequences for eggshell quality. British Poultry Science 40:5, pages 585-591. https://www.tandfonline.com/doi/abs/10.1080/00071669986945
A. W. WALKER. (1998). Retrieved on April 1, 2018 from Egg shell colour is affected by laying cage design. British Poultry Science 39:5, pages 696-699. https://www.tandfonline.com/doi/abs/10.1080/00071669888593
A. D. Mills, Y. Nys, J. Gautron, J. Zawadski. (1991). Retrieved on April 1, 2018 from Whitening of brown shelled eggs: Individual variation and relationships with age, fearfulness, oviposition interval and stress. British Poultry Science 32:1, pages 117-129. https://www.tandfonline.com/doi/abs/10.1080/00071669108417333
G. Beuving, R. B. Jones, H. J. Blokhuis. (1989). Retrieved on April 1, 2018 from Adrenocortical and heterophil/lymphocyte responses to challenge in hens showing short or long tonic immobility reactions. British Poultry Science 30:1, pages 175-184. https://www.tandfonline.com/doi/abs/10.1080/00071668908417135
Sarah E. Solomon, B. O. Hughes, A. B. Gilbert. (1987). Retrieved on April 1, 2018 from Effect of a single injection of adrenaline on shell ultrastructure in a series of eggs from domestic hens. British Poultry Science 28:4, pages 585-588. https://www.tandfonline.com/doi/abs/10.1080/00071668708416994
P. C. Glatz, A. B. Frensham. (1987). Retrieved on April 1, 2018 from Effects of relocation on production in caged layers. British Poultry Science 28:1, pages 119-128. https://www.tandfonline.com/doi/abs/10.1080/00071668708416943
A. D. Mills, Monique Marche, J. M. Faure. (1987). Retrieved on April 1, 2018 from Extraneous egg shell calcification as a measure of stress in poultry. British Poultry Science 28:1, pages 177-181. https://www.tandfonline.com/doi/abs/10.1080/00071668708416950
Articles from other publishers M.E. Hunniford, T.M. Widowski. (2018). Retrieved on April 1, 2018 from Curtained nests facilitate settled nesting behaviour of laying hens in furnished cages. Applied Animal Behaviour Science. http://linkinghub.elsevier.com/retrieve/pii/S0168159118300364
Albert G. Sellés, Bernat Vila, Àngel Galobart. (2017). Retrieved on April 1, 2018 from Evidence of Reproductive Stress in Titanosaurian Sauropods Triggered by an Increase in Ecological Competition. Scientific Reports 7:1. https://doi.org/10.1038/s41598-017-14255-6
20 common egg shell quality problems. Retrieved on Nov. 13, 2020 from Alltech store blog. https://store.alltech.com/blogs/poultry/20-common-egg-shell-quality-problems-and-causes
Avian reproductive system. Dr. Jacquie Jacob, University of Kentucky. Retrieved on August 20, 2024 from https://poultry.extension.org/articles/poultry-anatomy/avian-reproductive-female/#:~:text=The%20reproductive%20system%20of%20a,the%20ovary%20into%20the%20oviduct.
A. Gregorio Rosales. "Defective or Abnormal Eggs in Poultry - Poultry - Merck Veterinary Manual." Merck Veterinary Manual. n.d. Web. 26 Jan. 2018. <https://www.merckvetmanual.com/poultry/disorders-of-the-reproductive-system/defective-or-abnormal-eggs-in-poultry>
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
C.M. Sherwin, M.A.F. Nasr, E. Gale, M. Petek, K. Stafford, M. Turp, G.C. Coles. (2013) Retrieved on April 1, 2018 from Prevalence of nematode infection and faecal egg counts in free-range laying hens: relations to housing and husbandry. British Poultry Science 54:1, pages 12-23. https://www.tandfonline.com/doi/abs/10.1080/00071668.2012.757577
Dr. K.C. Sheppard, I.J.H. Duncan. (2011) Retrieved on April 1, 2018 from Feeding motivation on the incidence of floor eggs and extraneously calcified eggs laid by broiler breeder hens. British Poultry Science 52:1, pages 20-29. https://www.tandfonline.com/doi/abs/10.1080/00071668.2010.550600
S.E. Solomon. (2010) The eggshell: strength, structure and function. Retrieved on April 1, 2018 from British Poultry Science 51:sup1, pages 52-59. https://www.tandfonline.com/doi/abs/10.1080/00071668.2010.497296
Dr C.M. Sherwin, G.J. Richards, C.J. Nicol. (2010) Retrieved on April 1, 2018 from Comparison of the welfare of layer hens in 4 housing systems in the UK. British Poultry Science 51:4, pages 488-499. https://www.tandfonline.com/doi/abs/10.1080/00071668.2010.502518
V. Guesdon, A.M.H. Ahmed, S. Mallet, J.M. Faure, Dr Y. Nys. (2006). Retrieved on April 1, 2018 from Effects of beak trimming and cage design on laying hen performance and egg quality. British Poultry Science 47:1, pages 1-12. https://www.tandfonline.com/doi/abs/10.1080/00071660500468124
Frankie D. Jackson, Alberto Garrido, James G. Schmitt, Luis M. Chiappe, Lowell Dingus, David B. Loope. (2004). Retrieved on April 1, 2018 from Abnormal, multilayered titanosaur (Dinosauria: Sauropoda) eggs from in situ clutches at the Auca Mahuevo locality, Neuquen Province, Argentina. Journal of Vertebrate Paleontology 24:4, pages 913-922. https://www.tandfonline.com/doi/abs/10.1671/0272-4634%282004%29024%5B0913%3AAMTDSE%5D2.0.CO%3B2
Frankie D. Jackson, David J. Varricchio. (2003). Retrieved on April 1, 2018 from Abnormal, multilayered eggshell in birds: implications for dinosaur reproductive anatomy. Journal of Vertebrate Paleontology 23:3, pages 699-702. https://www.tandfonline.com/doi/abs/10.1671/A1092
M. Reynard, C. J. Savory. (1999). Retrieved on April 1, 2018 from Stress-induced oviposition delays in laying hens: Duration and consequences for eggshell quality. British Poultry Science 40:5, pages 585-591. https://www.tandfonline.com/doi/abs/10.1080/00071669986945
A. W. WALKER. (1998). Retrieved on April 1, 2018 from Egg shell colour is affected by laying cage design. British Poultry Science 39:5, pages 696-699. https://www.tandfonline.com/doi/abs/10.1080/00071669888593
A. D. Mills, Y. Nys, J. Gautron, J. Zawadski. (1991). Retrieved on April 1, 2018 from Whitening of brown shelled eggs: Individual variation and relationships with age, fearfulness, oviposition interval and stress. British Poultry Science 32:1, pages 117-129. https://www.tandfonline.com/doi/abs/10.1080/00071669108417333
G. Beuving, R. B. Jones, H. J. Blokhuis. (1989). Retrieved on April 1, 2018 from Adrenocortical and heterophil/lymphocyte responses to challenge in hens showing short or long tonic immobility reactions. British Poultry Science 30:1, pages 175-184. https://www.tandfonline.com/doi/abs/10.1080/00071668908417135
Sarah E. Solomon, B. O. Hughes, A. B. Gilbert. (1987). Retrieved on April 1, 2018 from Effect of a single injection of adrenaline on shell ultrastructure in a series of eggs from domestic hens. British Poultry Science 28:4, pages 585-588. https://www.tandfonline.com/doi/abs/10.1080/00071668708416994
P. C. Glatz, A. B. Frensham. (1987). Retrieved on April 1, 2018 from Effects of relocation on production in caged layers. British Poultry Science 28:1, pages 119-128. https://www.tandfonline.com/doi/abs/10.1080/00071668708416943
A. D. Mills, Monique Marche, J. M. Faure. (1987). Retrieved on April 1, 2018 from Extraneous egg shell calcification as a measure of stress in poultry. British Poultry Science 28:1, pages 177-181. https://www.tandfonline.com/doi/abs/10.1080/00071668708416950
Articles from other publishers M.E. Hunniford, T.M. Widowski. (2018). Retrieved on April 1, 2018 from Curtained nests facilitate settled nesting behaviour of laying hens in furnished cages. Applied Animal Behaviour Science. http://linkinghub.elsevier.com/retrieve/pii/S0168159118300364
Albert G. Sellés, Bernat Vila, Àngel Galobart. (2017). Retrieved on April 1, 2018 from Evidence of Reproductive Stress in Titanosaurian Sauropods Triggered by an Increase in Ecological Competition. Scientific Reports 7:1. https://doi.org/10.1038/s41598-017-14255-6
20 common egg shell quality problems. Retrieved on Nov. 13, 2020 from Alltech store blog. https://store.alltech.com/blogs/poultry/20-common-egg-shell-quality-problems-and-causes
Avian reproductive system. Dr. Jacquie Jacob, University of Kentucky. Retrieved on August 20, 2024 from https://poultry.extension.org/articles/poultry-anatomy/avian-reproductive-female/#:~:text=The%20reproductive%20system%20of%20a,the%20ovary%20into%20the%20oviduct.
