Hatch window

Dear Dr Hill,
I am neither a poultry specialist nor a veterinarian, just an intereseted onlooker with a suggestion. Sometime in the early '70s ornithologists studying wild ducks hatching eggs under controlled conditions, fitted microphones connected to recorders in the nest box. They found that about four days before hatching date, the mother duck started calling to her still unborn ducklings. A microphone placed below the eggs also picked up response calls from the ducklings within the eggs. The frequency of the mother birds' calls increased as the hatching date approached, with matching increase in response calls. Finally all ducklings hatched within hours of one another.
The scientists conducting the test concluded from this and other data, that the calling helped the chicks to hatch at the same time (essential for survival in the wild) and to imprint on their mother's call before birth. The full report was published in the Scientific American of that period.
Perhaps something similar happens during incubation in the domestic hen, though i have not come across a similar study report on them. Being ground nesting birds with precocial chicks, it is equally important for chickens to be hatch within a short time of one another. The calls of a mother hen then may be played back to chicks in an incubator to signal simultaneous hatching.
With best wishes,
Debashis Ray,

I feel this is a very informative article that stresses facts which cannot be found in text books, but are known only to a few with hands on experience. As stressed by the author, the most important factor in a hatch is to get the chicks to start eating and developing their digestive systems in the optimum time possible after they are ready to start and this is where the concept of the hatch window plays such a crucial role. Dr.Mahendra Choudri rightly underlines this when he he speaks about the first week weights which are so very detrimental in getting the final weights and F.C.R. Few hatchery men are actually aware of these concepts and. therefore need to concentrate more on this area. Thank you, Dr.Donna Hill.