I feed raw twice a day but not in their hutch as I find they take meat bones into the nest box. know people that have lost ferrets to botulism, problems from food hidden in the nest box. But who knows for sure.
I have a run on the lawn with pipes and hammock and old carrying box. it's covered over the top with polly tunnel plastic. After the evening feed I put a hand full of Alpha kibbles in a bowl, never any left. The one thing I think kibbles is good for is there teeth, it seems to keep the plaque off their teeth. having a mix I think improves their stools as well, firmer not runny.