Common egg quality problems

Approximately 2% of all chicken eggs has some defect, ranging from minor, barely noticeable faults to downright alarming deformities.
By sumi · Aug 27, 2013 · Updated May 3, 2016 · ·
  1. sumi
    Approximately 2% of all chicken eggs has some defect, ranging from minor, barely noticeable faults to downright alarming deformities. So the chances are pretty good that most, if not all flock owners will at some stage find an irregular egg. This article is about the most common egg irregularities and problems and their causes. A few members have asked me if these odd eggs are safe to eat. That depends on the cause of the deformity/irregularity. Most of these eggs, though some may look rather unappetising, are perfectly safe for human consumption. If the cause of the deformity/irregularity is disease or treatment for disease/pest I would play it safe and discard the eggs rather as many drugs given to chickens leaves a residue in their eggs during the withdrawal period (usually 3 weeks).

    To help us understand these problems and how they occur, let's first look at how an egg is formed:

    How an Egg is Formed

    An egg is formed over a period of about 25 hours. The egg yolks are formed in the hen's ovary. Hens, unlike most animals, have only one functional ovary, the left one. At the time of hatch each female chick will have up to 4 000 tiny ova, from some of which yolks may develop when the hen matures. At any given time, an active layer will have a number of yolks in her ovary, in different stages of development. (See pic in this thread for an example of what is in store in a productive hen's tract at any given time:

    It takes around 10 days for an egg yolk to mature, after which it gets released into the funnel (infundibulum) where, if live sperm are present, it will be fertilized. This process takes about 15 minutes. Next, the yolk moves down into the magnum, where inner and outer shell membranes are added, as well as water and mineral salts. This process takes about 3 hours. The yolk then moves into the isthmus, where albumen (egg white) is secreted and layered around the yolk. This process takes about an hour. Next the partly formed egg moves into the uterus, or shell gland, where it will receive it's shell. Initially some water is added, thinning the outer layer of albumen. Then the shell material, mostly calcium carbonate, is added, followed by pigments, if a colored egg is produced. For example a brown, blue or green egg. This process takes about 21 hours. Once this process is complete, the egg passes through the vagina and is laid by the hen. This final process takes less than a minute.

    For a virtual tour of the reproductive tract, see here:

    Common Egg Shell Quality Problems

    1. White banded egg


    These eggs are the result of two eggs entering and making contact with each other in the shell gland pouch. When this happens, normal calcification (egg shell formation) is interrupted and the first egg that entered the pouch will get an extra layer of calcium, seen as the white band marking. Causes for this are:

    - Stress in the flock;

    - Changes in lighting, for example adding artificial light in the coop to encourage laying over winter;

    - Diseases such as infectious bronchitis.

    2. Blood on egg shell


    This can be anywhere from a few spots to a smear to an alarming amount of blood. Causes are:

    - Small blood vessels ruptured in the hen's vagina from excessive straining. This is more common in young pullets coming into lay and overweight hens;

    - Cannibalism, vent pecking;

    - Sudden big increase in length of daylight (when supplementing light in winter months);

    - A mite/lice infestation around the vent.

    3. Body checked egg


    These eggs' shells got cracked during the calcification process and had a layer of calcium deposited over the crack before the egg was laid. Some body checks are covered by a thick layer of calcium, forming an noticeable ridge or band around the egg. Body checks will increase if the hens are exited or gets startled late in the afternoon/early evening, when the egg shell formation process begins. Causes of body checks are:

    - Stress and overcrowding;

    - The hen's age. There is a higher incidence in body checked eggs from older layers.

    4. Broken and mended egg


    These are similar to body check eggs. The egg shell got cracked during the calcification process and mended just before being laid. Cause:

    - Stress, frights or disturbance during the calcification process.

    5. Misshaped or odd shaped eggs


    These eggs differ from the normal shape and/or size and can be either too large, too small, round instead of oval or has major changes in the shape. Shapes can range from minor, barely noticeable to grossly mis-shaped. Causes are:

    - Immature shell gland (young layers);

    - Defective shell glands;

    - Disease such as infectious bronchitis;

    - Stress, frights, or disturbances;

    - Overcrowding in coop and/or run.

    6. Calcium deposits


    These egg shells have white coloured, irregularly shaped spots deposited onto the external surface of the shell. It can range from a few spots to a severe deposit, as shown in pic #6. Causes are:

    - Defective shell glands;

    - Disturbances and/or stress during the calcification process;

    - Poor nutrition, for example excess calcium in the hen's diet.

    7. Lack of pigment or uneven pigmentation on egg shells


    The causes for this can be:

    - Poor nutrition. A deficiency in any of the main nutrients, protein, minerals etc in the hens' diet can influence shell colour and formation. Zinc, copper and manganese are thought to be especially important in transporting pigment onto the shell. It has been suggested that a magnesium supplement can improve shell colour:

    - Viral infections. Infectious bronchitis and it's variants, Newcastle disease, egg drop syndrome and avian influenza can cause damage to the oviduct, resulting in loss of shell colour and other problems:

    - Internal and external parasites. A heavy infestation of roundworms and or capillaria worms as well as red mites, when present as a heavy infestation, can have an adverse effect on egg quality and may cause pale shells;

    - Drugs. The coccidiostat drug, Nicarbazin, if present in feed, can interfere with egg shell pigmentation;

    - The hen's age. And older layer will often produce eggs with paler shells, as well as a hen who had been laying intensively over a long period;

    - Stress. Physical stresses, environmental stresses or nutritional stresses can all interfere with shell pigmentation;

    - Exposure to sunlight and high temperatures can produce a fading effect on the shell.

    8. Calcium coated egg


    These eggs have an extra, powdery layer of calcium, covering either the entire egg, or just one end of the egg. Causes are:

    - Defective shell glands;

    - Disturbance or stress during calcification process;

    - Poor nutrition, for example excess calcium in the hen's diet.

    9. Speckled eggs


    Spots or speckles can be either brown or white. They are similar to calcium deposits, except the speckles are smaller. Speckles may or may not be pigmented. Causes are:

    - Stress or disturbance during calcification process;

    - Poor nutrition, for example excess calcium in the hen's diet.

    10. Shell-less eggs


    A shell less egg consists of a yolk, albumen and membrane, but has no shell at all. The egg contents are protected by the outer membrane only. These are often seen in pullets coming into lay. Causes are:

    - Immature shell gland (young layer);

    - Nutritional deficiency, usually lack of calcium and vitamins E, B12 and D as well as phosphorous and selenium;

    - Certain diseases, such as Newcastle disease, infectious bronchitis, avian influenza, egg drop syndrome;

    - Exposure to very high temperatures and extremely high or low humidity levels;

    - An infestation of internal or external parasites, such as worms, mites or lice;

    - Stress prompting the hen to lay an egg prematurely, before the shell is formed;

    - Egg laying while molting;

    - Exposure to toxins, such as mold, fungi, bacteria.

    11. Slab sided or flat sided egg


    When two eggs enter the shell gland pouch shortly after another, normal calcification is interrupted. The second egg will not be as complete as the first and may be flattened at the side where the eggs made contact, resulting in a flat or slab side. Causes are:

    - Disease, such as infectious bronchitis;

    - Stress, frights and disturbances;

    - Overcrowding in coop/run;

    - Sudden large increase in daily light hours, for example when supplementing light during winter months.

    12. Wrinkled eggs


    These eggs' shells have thinly creased/wrinkled surfaces. The wrinkles can range in severity from a single small wrinkle to quite a few large wrinkles, as shown in the egg pictured. Causes are:

    - Stress and disturbance during calcification process;

    - Disease such as infectious bronchitis;

    - Defective shell glands.

    13. Corrugated shell


    This happens when the egg membrane is thinner than it should be, often as a result of double ovulation (two yolks) and having to stretch thinner to cover the extra egg contents. This results in insufficient plumping of the egg, leaving a corrugated membrane onto which the shell gets deposited, so the shell takes on a corrugated appearance as well. Causes are:

    - Extra large egg size, often double or multi yolk eggs;

    - Newcastle disease;

    - Excessive use of antibiotics;

    - Copper deficiency in the hen's diet;

    - Excess calcium consumption;

    - A defective shell gland;

    - It is often seen with hens recovering from infectious bronchitis;

    - It can be hereditary.

    14. Yolk-less egg aka fart egg, fairy egg, witch egg, rooster egg or oops eggs


    These tiny eggs may or may not have a yolk. Yolk-less fart eggs are often called rooster eggs. These little eggs are often much darker than normal, as they spend more time in the shell gland pouch and gets an extra layer or two of pigment. These yolk-less eggs sometimes form when:

    - The hen's oviduct releases a small piece of reproductive tissue or another small foreign mass enters the hen's oviduct, triggering the regular formation of an egg. The foreign object will be treated like a normal yolk and enveloped in albumen, membranes and a shell;

    - Occasionally a hen will also lay a fart egg when something disturbs her reproductive cycle;

    - Young pullets may lay a fart egg or two when coming into lay and is still getting their reproductive systems in gear.

    15. Soft shell eggs


    These eggs are laid with an incomplete shell, sometimes just a thin layer of calcium. Causes are similar to shell less eggs:

    - Immature shell gland;

    - Nutritional deficiencies, usually lack of calcium, vitamins E, B12 and D as well as phosphorous and selenium;

    - Disease such as infectious bronchitis, avian influenza, egg drop syndrome; an internal or external parasite infestation;

    - Exposure to very high temperatures and/or very high or low humidity levels;

    - Egg laid prematurely due to stress or a disturbance during the calcification process;

    - Egg laying while molting.

    16. Mottled egg shells


    In mottled egg shells parts of the egg shell are translucent, taking on a mottled or glassy appearance.

    These shells can also be thin and fragile. Causes are:

    - High humidity in the coop (make sure the coop is well ventilated;

    - Certain diseases, (such as infectious bursal disease) and mycotoxins;

    - Manganese deficiency in the hen's diet;

    - Over-crowding in the coop.

    17. Holes in egg shells


    Pinholes, or small holes in the egg shell, may be the result of faulty laying down of the egg shell or from pimples being knocked off the shell. Possible causes are thought to be:

    - Advanced layer age

    - Poor nutrition

    - Damage from toenails, or other sharp objects in the nest box, post laying.

    Common Yolk Quality Problems

    1. Blood spots

    blood spot - pic by Melabella.jpg

    Can range in severity from a small spot of blood on the yolk to about a spoonful of blood mixed with the egg contents. Egg yolks form and mature in the hen's ovary and sometimes when the mature yolk is released it may rupture a small blood vessel, the blood released will end up being encased in the shell, along with the rest of the egg contents. Causes of this can be:

    - Incorrect levels of vitamins A and K in the hen's diet;

    - Administration of the drug sulphaquinoxaline;

    - Large amounts of lucerne meal in the layers' diet;

    - Feeding stale, wet or mouldy feed;

    - Continuous lighting in the coop;

    - Frights, stress and disturbances.

    2. Pale yolks


    Can be caused by:

    - Lack of yellow to red pigments in the hens' diet. Hens who have access to the outdoors, green food such as lucerne and grass and hens who are fed maize will have deeper coloured yolks. Certain feeds contain additives, such as marigold extract to help deepen the yolk colour.

    3. Mottled yolks


    Can be caused by:

    - Worming drugs and compounds piperazine, dibutyltin dilaurate and citrate;

    - The anticoccidial drug Nicarbazin;

    - Certain antioxidants such as gallic acid and tannic acid;

    - Feeding hens raw soybean meal;

    - Calcium deficiency in the hens' diet;

    - Thin egg shells;

    - Can be hereditary.

    4. Discoloured (blue-green) yolks


    Can be caused by:

    - Feed or snacks containing cottonseed oil;

    - Ingestion of the weed Shepard's Purse.

    5. Double or multiple yolk eggs


    These are more common with your pullets just coming into lay. This happens when more than one yolk matures and gets released at the same time. As many as 9 yolks have been found in a single egg.

    6. Rubbery, cheesy or pasty yolks

    Are caused by:

    - Ingestion of crude cottonseed oil;

    - Severe chilling or freezing of intact egg;

    - Ingestion of velvet weed and other related species.

    7. White or platinum yolks


    Can be caused by:

    - An infestation of cappilaria worms and certain diseases.

    Common Albumen Quality problems

    1. Meat spots

    [​IMG] [​IMG]

    These are usually little bits of the lining of the oviduct which got shed during the egg formation process, but some may be partially broken down blood spots. They often take on the apearance of dirt or soil and vary in colour from pale yellow to dark brown or red, as shown in the images. Sizes vary from tiny specks to a few millimetres in diameter. There is a higher incidence of meat spots in eggs from older layers.

    2. Thin, watery albumen

    This can be caused by:

    - Disease such as Newcastle disease, infectious bronchitis, laryngothacheitis or egg drop syndrome;

    - High egg storage temperature;

    - High level of ammonia from droppings in coop (inadequate ventilation/coop hygiene);

    - Loss of CO2 from egg during storage;

    - High vanadium levels in feed;

    - It can occasionally be a reaction to certain vaccinations.

    - There is a higher incidence in eggs from older layers.

    3. Off colour albumen


    For example pink or green. Cause:

    - Spoilage due to Pseudomonas bacteria produces a greenish, fluorescent, water soluble pigment in the albumen.

    - A green tint to to albumen can also be caused by the presence of high levels of riboflavin (vit B2), which has a yellow green colour.

    For more information on eggs, egg laying and egg layers visit the chicken behaviors and egglaying forum section.

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  1. BeulahBreezes
    Thanks so much for this information! I have used it so many time, it's been a great help! Beulah
  2. crazyfeathers
    Very informative. Thanks
      sumi, casportpony and black_dove2 like this.
    Fascinating information! WOW!
      casportpony, black_dove2 and sumi like this.
  4. mymilliefleur
    Great article. I have a hen that lays body checked eggs on a regular basis. I think it has to do with her age though, as she is not a young hen.
      casportpony and black_dove2 like this.
  5. Yardwork
    I'm new to this amazing world of chickens and loved the article. My BCM's are young and I believe one or two of them are easily frightened which is causing #1 to occur. Thanks for this wonderful resource.
      casportpony and black_dove2 like this.
  6. autumnhearth
    I love our speckled eggs but we also get occasional calcium deposits, sounds like our girls might be getting too much calcium.
      casportpony and black_dove2 like this.
  7. Honomi
    Thanks. It's very helpful. My chickens have been laying eggs just like some of the pictures shown above, #1, 11 and 13, and as my girls both have been gasping/ gaping air quite a lot lately again, so "infectious bronchitis" is convincing.
      casportpony and black_dove2 like this.
  8. Dee Dee 2
    Great article ! Thanks for taking your time to write it. Quite helpful !
      casportpony and black_dove2 like this.
  9. collingwood
    Yeah really hellpful!
      casportpony and black_dove2 like this.
  10. TheChickenQueen
    Great article! Now I have some awnswers to some of my questions :)
      casportpony likes this.
  11. MsPoultry
    Cool info weird eggs
      casportpony and black_dove2 like this.
  12. Kidhenduckohmy
    So what if I have quite a few of these problems? I have had chickens for about three years, and I have had: corrugated shells, wrinkled eggs, flat sided eggs, speckled, calcium coated, calcium deposits, misshapped and odd eggs, broken and mended, body checked, and white banded eggs. I have had about three shell-less and one soft shell. I have had quite a few blood spots and some meat spots. I guess I always just thought strange eggs were common as I have always gotten them. The chickens seem happy and healthy and I have never seen parasites on them. So where do I go from here?
      black_dove2 likes this.
  13. SkyWorld
    Great info for a new egg like me! Helps me on how to spoil my girls and still be careful of how stress and problems can be introduced. I will look more carefully at what they need, Thanks.
      black_dove2 likes this.
  14. Chickenchick11
    This is great! Keep up the awesome work. [​IMG]
      black_dove2 likes this.
  15. sumi
    Thank you for the kind words, NorthFLChick. I'm glad to hear the article is helping :)
      black_dove2 likes this.
  16. N F C
    I've referred to this article a couple of times and always walk away having learned one more new thing. Thanks for the very helpful information. One of my RIR's laid a soft shell egg just today and it was great to be able to find out the possible causes of it from this article. Thank you!
      black_dove2 likes this.
  17. JKRopee
    Great information, thanks to all who contributed!
      black_dove2 likes this.
  18. judyki2004
      black_dove2 likes this.
  19. misslys15
    I get speckled eggs from a few of my hens, but not all of them. They just eat normal layer feed, snacks that we give them (mostly fruit and oatmeal, never any processed food), and whatever worms, bugs, grass, etc. they can find. They all eat the same thing, so I can't imagine the three hens who lay speckled eggs are getting too much calcium, while the others are not? It's not from stress because they've been doing it since they started laying, and they're quite happy with their set-up. Is it possible that some breeds lay more speckled eggs than others? I regularly get speckled eggs from my Barred Plymouth Rock and my Golden Laced Wyandotte and my Golden Comet has laid one egg so far, which was speckled. However, my Rhode Island Red and Tetra Tint lay solid colored eggs.
      black_dove2 likes this.
    1. nightowl223
      Some breeds, and some of the birds in other breeds, lay speckled eggs normally, not as a sign of anything wrong. This should have been clarified in the post, but was not, for some reason.
  20. sumi
    SaidBlackSmith, I've looked for more info on that, but I haven't been able to find a good reason for it so far. If I do I will let you know.
      black_dove2 likes this.
  21. Rochafam4
    Very helpful!! thank you!
  22. SaidBlacksmith
    About the 'Wind Eggs'- Every article says they're normal unless they lay more than a few- then there should be concern- but they **never** say what the concern is! Can you add any insight to excessive wind eggs?
      black_dove2 likes this.
  23. Mountain Peeps
    Amazingly helpful! Good job Sumi!
      black_dove2 likes this.
  24. sumi
    jerrey, I'd go through the causes above and eliminate according to feed (are you feeding them correctly?), stress (is anything bothering them, like a predator?), parasites (have you dewormed/dusted them for mites?), disease (showing any signs of?) etc. If you hen is young and the soft egg was a once off I wouldn't worry though. Young hens sometimes lay soft eggs while they're working out the kinks in their reproductive systems.
      black_dove2 likes this.
  25. sumi
    blmack, no, unfortunately not, unless you have a very good light for candling, as they use on commercial egg farms, but then even they miss them. I've found many meat spots and blood spots in "shop eggs". The pic above of the 2 boiled eggs with the meat spots were store bought eggs.
      black_dove2 likes this.
  26. jerrey
    so what should I do for the soft egg shell
      sumi likes this.
  27. blmack
    I like to give away eggs to friends and family, but don't want to give eggs that have meat spots or blood spots. Is there a way to tell before cracking the egg?
      sumi likes this.
  28. sandman55
    A very helpful article thanks.
      sumi likes this.
  29. Crzy Chi Lady
    Thank you for this useful and well put together information!
      sumi likes this.
  30. rolito tabujara
    Very educational. Thank you for the effort to share. God bless!
      sumi likes this.
  31. chiengora
    Very interesting, thank you. Fortunately, I have only seen a few of these problems.
    My biggest issue is convincing the hens to lay in the nest boxes where i can easily find the eggs and my dogs can't.
      sumi likes this.
  32. ChickenIsh
    My Giant Cochin lays an egg with a calcium layer every time, and she has since she started laying. If I run it under the water it immediately turns a dark brown, almost as brown as my Black Copper Marans' eggs but as soon as it dries it turns back to a frosty pink color with a sandpaper feel, I thought it was strange and figured it to be a defect but it doesn't bother me, she lays the biggest eggs of all of our chickens! I also didn't know that brown spots on the egg was a defect, I thought it was just another natural way of pigmenting, a lot of my chickens lay eggs with speckles, I quite like them, they're my favorite next to the olive colored eggs. This is a great article, thanks!
      sumi and black_dove2 like this.
  33. brendi
    Thank-You for the info!!! We are new chicken owners we have one silkie, a sizzle and one frizzle. all three of our girls lay eggs. This has been VERY helpful .
      sumi likes this.
  34. Fanny's Mom
    Love this article. Answers a lot of questions for me!
  35. m96tacoma
    My hens have had some of the issues here with the reasons (according to the articles) being a medical problem i.e. infectious bronchitis, or mites. I haven't noticed any thing wrong with them, not sick at all. I shouldn't worry, right?
      black_dove2 likes this.
  36. TheKeeper
    Awesome article. Thank you to all the contributors!
  37. mfuqua
    Great resource. Thank you for fantastic information and the photos to go with it.
  38. Wishapup
    I was surprised to read that speckled eggs were an issue. Good article!
      black_dove2 likes this.
  39. LittleBits
    Thanks for this article. Lots of information I've been wondering about and it's now in my "Chickens" folder!
    Why does a hen lay an egg in the middle of the night while on the roost? Sometimes they've been regular, hard-shelled eggs but more often it's a soft-shelled. Are the soft-shelled eggs OK to eat?
      black_dove2 likes this.
  40. sumi
    It sounds like the hen passed the egg before the yolk and membrane got to the isthmus, where the albumen gets deposited. (See the second paragraph, on how an egg is formed). She may have got a fright or got disturbed at this stage, causing her to "abort" the egg.
      black_dove2 likes this.
  41. Nutcase
    Today one of my hens laid a weird egg. It was large, soft, orange and rubbery and when I broke it was all yolk and no white. The closest match on this article is the shell-less egg. I'm thinking it may have been caused by the recent change in layer feed.
  42. anirishfarmer
    great information thanks a lot !!!!!!!!!!!!!!!
    keep up the good work
  43. sumi
    Thanks everyone! I'm hoping to find more pics to add to this article in future, especially for "yolk problems". So if anyone has a pic I can use, or finds a yolk/shell problem that I've addressed, but haven't posted a pic of yet, please PM me.
  44. Nutcase
    Answered my questions too! Really helpful, thanks sumi!
  45. houseofknauss
    this is perfect-it answered some questions I had--awesome!!!!!!!!!!!!!!
  46. redsoxs
    Top-notch article, Sumi! I learned a lot!
  47. Mac14
    Really cool! It's great to know why that happens.
  48. LaLa Chickie
    You are very welcome. Glad you liked it...La La and Cha Cha are laying perfect eggs now...
  49. Carin
    Thanks Sumi
  50. ChemicalchiCkns
    Official reference Work.

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