bottom of my bunnies 2 back feet

Question
Hi,
I have a young, active bunny (over a year old) who is definately not in pain or sick.  He was stretched out last night on the floor, and I happened to look closely at the bottom of both of his feet and noticed something.

He had circular, hairless pink spots on the bottom of both feet, at approximately the same spot on each foot.
One was a little bigger in diameter than the other.

Are they sores?  Or are they normal?

I have another bunny and she doesn't have that.
I know rabbits do not have pads on the bottom of their feet like cats and dogs.

We adopted him 3 months ago, so we don't know his history before then.

Should I look into this?

Regarding his breed - he must be a mix, since he's only 5 lbs, but he looks just like a chinchilla rabbit.

Any advice would be appreciated.
Thanks in advance

Answer
hi-some breeds of rabbit suffer from what we call sore hocks-rex are particully vunerable.
it imperative they have soft bedding such as sawdust to run on this will prevent the hocks going bare.
see how he goes and if they are troubling him take him to a vet how should give him something.
dave.