Chin chewing on feet

[mochachino17]

My male chinchilla started chewing on his feet about a week ago and I don't know why. He would chew on them until they bled, and I had to put a hand-made cone on him. His feet are finally healing and the doctor said they aren't infected, but they couldn't figure out why he was chewing on them. They thought he might have had some edema from the heat wave and was only trying to relieve the pressure, but I'm afraid that he might have fur fungus. Are there any certain signs of fur fungus? I have a female housed with him and she's never been a fur chewer and doesn't have any signs of fur fungus.

 

[Rara814]

What kind of bottom do you have in your cage, is it solid or wire? Is there any bedding?

 

[mochachino17]

It's solid with recycled paper bedding. They have ledges, houses, and multiple levels in their cage.