a scientific study could be done but it would be complicated because you would have to take into account each participants latitude and longitude , the breeds of the chicks, the exact minute and day of hatch , and more i’m sure , things like what feed they were on and brooder types and temps and other factors regarding housing and size of flock and when first egg was layed , daily weather, were there other kinds of poultry around ( geese, ducks, etc ) and etc etc it could take several years to figure out