Bald spots shouldn't be a worry if you ask me, for that my bird and my cousin's dog would have patches of missing fur - it'll grow back.
One thing though, if he's itching and constantaly scratching it or biting it, this could be a sighn of a skin irritation. My Miniture Collie ***** whent through this and she had a big bald spot on her rump.
When Bun-Bun goes through that winter-shed when spring arrives, it's absoutly horrible. Hair every where you couldn't come out of my room whith out tracking hair in the rest of the house.
One thing I did, was I took Bun-Bun out side in the middle of the back yard, and just ruffled the dead fur from him. Just rub your hands all over him and the fur will become even looser for you to just whipe off or pick off. Put a towl over his head, though, you don't whant hair to get in his eyes or nose.