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, double shelled or rough shells is much higher in hens who live under stressful conditions.
Conditions which cause defective eggs:
Stress induced oviposition (egg in wrong position inside the hen).
Deep litter
Moving hens from pens to cages
Rough handling
Vitamin deficiencies
Vaccination during production
Viral diseases such as, bronchitis, egg drop syndrome, and Newcastle disease
In rare cases, foreign material that enters the oviduct through the vagina (eg, a roundworm) may be incorporated into an egg (A. Gregorio Rosales. Mercks. 2018).
Conditions which cause defective eggs:
Stress induced oviposition (egg in wrong position inside the hen).
Deep litter
Moving hens from pens to cages
Rough handling
Vitamin deficiencies
Vaccination during production
Viral diseases such as, bronchitis, egg drop syndrome, and Newcastle disease
In rare cases, foreign material that enters the oviduct through the vagina (eg, a roundworm) may be incorporated into an egg (A. Gregorio Rosales. Mercks. 2018).
Causes of Rigid, Sunburst, Slab-sided, Soft Shelled, or Double Shelled Eggs
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.
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.
Rough Feeling Shells
Ridges, pimpled or rough feeling shells, are eggs that have stayed in the shell gland too long.
Blood Spots
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).
Meat Spots
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.
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).
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.
Rough Feeling Shells
Ridges, pimpled or rough feeling shells, are eggs that have stayed in the shell gland too long.
Blood Spots
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).
Meat Spots
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.
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).
Abnormal Egg Shells Caused by Hen Stress
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).
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
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
