Day old chicks, available from hatcheries, may be fed but not to the exclusion of other foods. Only in small amounts, just once a week. Nursing jills will benefit if they are fed a teaspoon of raw lambs liver every day. BUT, does not contain all the vitamins and protein needed. Can be fed occasionally but avoid cured, salty or very oily fish.
Some fish can cause a thiamine deficiency in a ferret.
Once a week as a treat. Too much can lead to baldness but this might be avoided by hard boiling the egg. It causes loose and smelly droppings and gives rise to dental problems. Ferrets need something to chew for strong teeth and healthy gums. Water the milk down and the laxative effect will be reduced.