Clear eggs tend to be the most prevalent in the first round or two. These are the eggs which never begin development because of being infertile. The testicle in the cocks get quiescent during the shorter daylight periods. Breeding activity reawakens them and they begin producing sperm and testosterone at a higher level.

While this process is under way, there is often a low sperm count and a lower sex drive in cocks. Frequently the breeding vigor and frequency is decreased as well a there being diminished sperm in the ejaculate.

All these can produce infertile eggs. One or both eggs being infertile in the first round is a frequent finding sometimes running as high as 50% or more of the eggs. The weather plays some role in this. Colder, darker periods accentuate the problem.

Eggs which begin developing but fail to fully develop and die in the shell can be the result of several things. Poor incubation can cause embryo death. Here the parent(s) may fail to keep the eggs warm for even a short period during very cold weather.

Eggs getting jarred excessively at critical points of development may also perish. Infection in the egg is probably the most common cause. The infection may be incorporated in the egg by hens having an oviduct infection. Infection more frequently occurs through the shell.

This can happen during laying as they often become contaminated with feces during this process. It can also happen by fecal contamination after laying, frequently from parents defecating in the nest or tracking feces in the nest on their feet.

During damp periods, nesting material often gets high numbers of bacteria in it from parents tracking feces and the dampness and warmth of the sitting parents encourage bacterial growth. The higher the numbers of bacteria around the eggs the easier it is to have penetration of the shell and subsequent infection of the embryo.

Babies dying in the first few days of life occurrs when they are infected either in the egg, resulting in weak hatchlings, or they become infected after hatching. After hatching they can become infected from the crop milk from either parent or from the nesting material.

During damp periods it is often helpful to change the nesting material just prior to the eggs hatching as infection enters the squabs easiest just after hatching through the umbilical area which is yet unsealed.

When certain parents experience repeated deaths in newly hatched babies, they should be separated and treated with a broad spectrum antibiotic for about 10 days, and for trichomonas, then remated. Pay attention to the condition of the nesting material during the times mentioned above and provide clean dry nesting material as indicated.

There are other factors which may cause the problems discussed here. Only the most frequent caused were discussed here.

Babies which die in the egg (as long as the shell remains intact) and babies which die soon after hatching are often valuable specimens for culture. A culture can be very revealing as to cause of death and possible course of action to prevent future deaths.

Dr. David E. Marx D.V.M.