not sure what raw milk is going to do for regrowing feathers and too much milk and the chickens will be squirting like crazy. They can handle a bit of fat but too much... not good.
besides raw milk is expensive if you can find it. Cottage cheese is cheap and easy to to find. Even using...
Either she is being peck by other in the flock or she is pecking herself. She may have mites or lice, or she is being pecked on for a behavioural problem namely boredom or even poor nutrition.
Regardless the bald spot needs something like bag balm, ( drugstore ) udder cream (...