Expert knowledge. Expert opinion.
Expert formulas.

Troubleshooting egg shell quality issues in your flock

A bright yellow yolk from a freshly laid egg is a key benefit of home produced eggs. However, packaging is important for the perception of quality and egg shell quality is one issue that sometimes crops up with laying flocks – especially in the spring as birds come back into lay. When a flock has an increased incidence of egg shell quality issues, the following checks may assist with troubleshooting. Feed intake and quality

A good quality layer feed that contains balanced levels of calcium, phosphorus and vitamin D should always be available for birds. A laying chicken should eat approximately 130 grams of layer feed each day – if the amount of layer feed eaten drops, this can have an impact on egg shell quality. Housing until after they have eaten a hearty breakfast can sometimes stop them filling up on less well-balanced herbage. If birds have a lot of alternate feeds on offer as well as their layer feed (e.g. whole grains or table scraps), this could also be decreasing their layer feed intake. Oyster grit can aid gizzard function and help to balance low calcium feeds birds may consume when foraging – but it must be offered separately to the layer feed, not sprinkled on top. Access to good quality water is also important, as reduced water intake results in reduced feed intake. High temperatures can reduce feed intake too, so over summer make sure chickens have access to cool water and shade.

Disease in the flock

Some diseases can affect egg shell formation and cause eggs to be laid with thin shells, misfired shells or with no shell at all. Two common diseases which can result in poor shell quality are infectious bronchitis and egg drop syndrome. Regular cleaning of coops with a disinfectant product such as Virkon®S, as well as preventing contact with other birds will help with minimising disease burden in your flock. Check with your local veterinarian for vaccination options.

Egg size/age of chickens

Hens will deposit the same amount of shell for a small egg as a large egg. This means that there is less shell to go around a larger egg and thin shells can result. Older birds will naturally lay larger eggs that have thinner shells, so aging chickens may be the culprit.

Rearing of chicks

How a chick has been reared can impact on how they will perform as a layer. If a chick is not supplied a diet with balanced levels of calcium, phosphorus and vitamin D, it can have an impact on bone development and when they eventually get to point of lay they will be more predisposed to laying thin-shelled eggs. It is therefore important to use a well-balanced chick starter feed followed by a balanced pullet grower feed.

Feeding over a moult period

Laying chickens will typically go through a moult with the approach of winter and decreasing day length. During this period, egg production will decrease and may even stop. Believe it or not, what you feed a chicken over the moulting period can impact on egg shell quality in the next laying season and if a diet is too high or too low in calcium it can be an issue. The recommended feed for chickens going through a moult is a pullet grower feed, as it contains the right amount of both calcium and phosphorus. As soon as the moult period is over and chickens begin to lay again, they can be switched back over to a laying feed.

Nesting box and bird management

The design of nest boxes as well as the quality and depth of nesting material plays an important role in preventing damage to egg shells. Nests require 5cm or more of bedding material to provide a soft landing for the eggs.


Any factor that causes stress to the birds can result in poor shell quality. Make sure wild animals are not able to disturb the birds and that a good routine is established and maintained.


For further information, contact your local Nutrition Specialist.

Article supplied by Stacey Cosnett, Nutritionist.