If eggs break at collection, crack in the tray or turn up “in a bag” with no shell at all, you cannot just live with it: you lose money, and the birds may be ill. Below are the typical causes in order of likelihood.
Seven causes
- Not enough calcium. The most common cause: complete feed was diluted with grain, the oyster shell ran out, or chalk dust was used and was gone by night. More in the article about calcium.
- Not enough vitamin D3. Without it calcium is not absorbed, even if there is plenty. In winter with indoor housing there is usually little unless the feed is fortified.
- Unbalanced phosphorus. Excess phosphorus interferes with calcium absorption. It happens in home-made diets without control of composition.
- Heat. Above 82–86 °F (28–30 °C) birds pant, the acid-base balance of the blood changes, and calcium deposits less well in the shell. Shade, ventilation and cool water help.
- Age. Older hens lay larger eggs with thinner shells, since the same shell has to cover more egg. Such a bird is a candidate for replacement.
- Stress. Fright, noise, a predator: the egg can be held back and come out shell-less or uneven.
- Disease. Infectious bronchitis, egg drop syndrome and some other infections damage the oviduct. Shells can be rough, misshapen or pale in many hens at once. Mold and mycotoxins in feed are harmful too.
What to do, step by step
- Check the feed. It should be layer feed. How much grain do you add? The more grain, the lower the share of calcium in the diet.
- Offer coarse oyster shell separately and wait 1–2 weeks: shells do not improve at once.
- Check vitamin D3 in the feed or supplement. Do not exceed the dose set by the manufacturer.
- Assess temperature and water in hot weather.
- See how many hens are affected. A few eggs point to diet or age. Many hens at once, especially with coughing or a drop in production, means calling a vet.
Shells are bad in many hens at once, and there is coughing, wheezing, diarrhea or mortality. You need a diagnosis, not supplements at random.
Can you eat these eggs
Cracked eggs must not be stored: bacteria get in through the crack. Use them the same day and only fully cooked. Eggs with a soft membrane instead of a shell should not be sold.
Watch the breakage rate
If you count breakage as a share of all eggs collected, the trend is visible at once: about 2% is usual, 5% and rising is a reason to check the diet. If you notice breakage, record it on the day of collection, and a week later you will see whether your measures helped. If production is also dropping, see the checklist of causes.
