I have given kittens extra milk when their young rescue mommy was struggling.
This recipe was given to me by Dr. Nancy Scanlon, DVM. Kittens (and cats) need the fat
in whole goat milk. The exact amount of milk ratio escapes me - maybe a cup or two-
I will look it up at home later - but it included a fresh egg yolk (I try to only buy free range)
and 2 tablespoons of olive oil, and maybe (if memory serves) a teaspoon of honey.
I am not sure if I ever gave the honey! However, they definately lapped up the goat's milk,
egg YOLK (not white, not good for them) and olive oil mixture. They are big and healthy
13 year olds now. And egg yolk, by itself, is full of B vitamins and healthy fats.
Good luck!