Baby Boy is loosing hair under his arms

[My boys]

Boy I thought I had this raising a squirrel down pat but I guess you never do!
Baby Boy is loosing hair under his arms there are no marks like bruises or cut's but I'm really concerned about hair loss.
I know you all can help thank you in advance 8)

[stepnstone]

When that happened to my little girl I looked for a cause, rubbing, fleas, anything. I couldn't come up with an answer.
Since I do let her go outside in a cage and there are other squirrels that come around when she's out there, I decided to treat her for mites just in case. Must have been it because after just 1 treatment her fur came back. :dono

[My boys]

I don't let him go outside but I have dogs they don't have any fleas or like that but I think I'm going to treat him with revolution anyway.
Thank you for your help

[stepnstone]

I don't let him go outside but I have dogs they don't have any fleas or like that but I think I'm going to treat him with revolution anyway.
Thank you for your help

I even looked for mites using a jeweler magnifier on her, shaking out her bedding on black paper, checking through her nest box, never found or saw anything on her. I just know after the treatment her fur came back in and rather quickly too, so it had to have been something I couldn't detect. Also as a precaution to rubbing or irritation, I enlarged her nest box hole a 1/4" and started washing her bedding only in dawn dishwasher soap with a double rinse. Got to take care of our babies. :thumbsup