Clear eggs occur often early in the breeding season, before birds are really in breeding condition. Hastiness in putting birds together can waste a considerable amount of time and breeders who rush the season can easily find themselves apace with more patient breeders in a story reminiscent of The Tortoise and The Hare . . . A breeder of my acquaintance waits until nearly March before putting his birds together, allowing them to come into condition naturally without the use of any breeding stimulants at all except light and comes up with nearly two hundred babies after a single round of nesting every year. Every nest has four or five babies and he experiences very few clear eggs. Other breeders beginning in December have to breed three rounds with the same number of hens to come up with the same results- often finishing the season later than the patient breeder!

Fertility can be affected by unstable perching which does not allow successful copulation. Obesity in either male or hen can also make copulation more difficult and impact fertility.

The time span between mating and the laying of fertile eggs is a matter of debate. Some breeders believe that 24 hours is the minimum period of time and others that four or five days are required between mating and commencement of laying for all eggs to be fertile. One day is cutting it rather fine, but it is possible.

Eggs can continue to be fertile for a considerable time after mating. Anecdotal evidence indicates that fertile eggs have been laid weeks after a hen has mated, although this time span is probably not common.

For all eggs to be fertile, males used for stud should be in the cage at least through the laying of the fourth egg. Males can be run with one hen in the morning and placed with another in the afternoon or left in one hen’s cage all day. Hens can sometimes become overly attached to a male and refuse to sit without his presence- with these birds, leaving the male in the breeding cage until the hen has been sitting for several days can help as she is fairly well attached to her duties by this time.

Further reading:  Infertile Eggs by Robirda