These embryos also retain fluids around the eyes, have shorter beaks, curled toes and poor muscle development in the legs. It's time to change from maintenance rations to breeder rations for your birds. The diet fed six weeks prior to the laying of the first egg determines the hatchability and strength of the chicks. With ornamental pheasants and chickens which are closely line-bred, a vitamin supplement added to the breeder diet will greatly increase the hatchability of fertile eggs and result in stronger chicks. Fertility declines as birds age.
Exotic pheasants show a decline after about four years.
Ducks maintain a high level of fertility for four to seven years while geese are fertile for up to ten or fifteen years. Domestic poultry and waterfowl for commerical purposes are rarely kept after the second year of breeding because of the decline in fertility.