I am thinking possible zinc deficiency or an imbalance of zinc/copper
The thing w/zinc is it is usually abundant in raw food especially baby calf's liver, however it is also easily deficient at times of illness, season changes, stress, pesticides/toxins, immune suppression from vaccination and so on.
Zinc is very importance for immune function but NOT a lot is needed, but some might be to get back in balance...it is also related to skin sores, hair loss and inabilty to heal....
look at the food you are giving in weights (oz.'s) and go to nutritional data.com and see if what you are feeding may not have the right ratio's.
Copper def. is rare and is found in meat, fish and liver
Zinc is also found in the same, as well as eggs, pumpkin seeds.
I think the link says zinc to copper 10:1 ratio
If you suppliment zinc - use a natural form or amino acid chelete form - low dose so you can regulate it (15mg.) then you cna do 30 - if you buy 50mg, may be too much.
I only suggest this as you are doing RAW, for anybody else, if on a kibble diet you have NO WAY of knowing how much is in pre-mix and sprayed on, blood work may help, but different batches of food can provide different values.
Supplimenting with a zinc/copper all in one may prove to help if you think the ratio's in RAW food is fine