From the book "The Complete Herbal
Handbook for the Dog and Cat" by Juliette De Bairacli Levy. 2 excerpts:

About prey eating (pp 15-16):

"In the wild, hair and underskin are part of a natural flesh diet and supply
essential roughage to exercise the strong muscles of the digestive tract,
acting also as a mild laxative....
Animals in the wild, after tearing off some outer skin and flesh of their
victims, unfailingly show a preference for certain organs of the body: first
the intestines, then the eyes. The intestines supply a good source of
demi-digested starch and green herbage.... The other chose organs are the
eyes, which animals gouge out with great eagerness. (Seagulls, which are
partly carnivorous, always greedily seek the eyes of drowned bodies, animal
or human.) It is no doubt some mineral salts which attract the carnivorous
animals, phosphorus and iodine normally being present in the eye tissue. Dr
Weston A. Price.... states: '.... they know that the tissues forming the
back part of the eye are good for food. Science has recently demonstrated
that the retina of the eye is one of the rich sources of vitamin A.'.."

About eggs (p 38):

"Eggs from hens, ducks, or turtles are a rich source of mineral salts and
vitamins.... Eggs must be fresh, as staleness renders them indigestible.
They should be fed raw, because cooking causes them to adhere to the
digestive tract.... Eggs are quite a natural food to the dog, for dogs will
seek out and eat the eggs of sea-birds and other birds, such as game-birds,
which lay their eggs on the ground. Eggs are very *unsuitable* food for sick
animals because of their highly fermentative properties. During the heat of
fever, for instance, they rapidly poison the body instead of strengthening
it. Egg-and-milk has long been the most misguided of orthodox
medical-recommended invalid foods; the giving of such food has done about as
much to spoil cures by orthodox treatment as has the popular use of the
destructive sulphonamide group of drugs. It is claimed that raw egg-white
harms health: I do not agree. Egg-stealers, such as foxes, weasels, cats and
rats keep very well, thank you!"