Hi,

What kind of diet do the cats eat? It is ultimately the best if they are eating a raw food diet, and maybe they are already. Either way, here is a great website for it.
http://www.catnutrition.org


Otherwise try adding essential fatty acids to their diet, such as flax oil, Udo's Choice, fish oils or something they will happily eat. Good to offer them a variety. You could try tuna in oil or sardines in oil. Some cats like to lick vitamin E capsule oil, so get a high quality oil.

EFA's will help tremendously.

Also keep on brushing them.

Good luck to you and the kitties.

CK

I put a dollop of coconut oil on top of my cats paws during the shedding season. They lick it up and come looking for more too.