What a chub! We had a lonely only once that looked like that. Eventually, I separated him from momma and only put him in with her twice a day for an hour or so. I was afraid he might develop splay leg. He grew up to be the best rabbit we ever bred and became our herd sire. He looked so fat as a kit, but grew up to be a big, meaty buck.
There's a thread about Pudge and his progress and I can find it for you if you want it, but I've posted the link to it fairly recently and you may have already looked at it.