If at all possible I would try to catch him...I know how hard this catching a rooster can be though and you don't want to add any additional stress. If he is not gushing blood, limping, and by all means acting normal keep him in a clean area and keep an eye on him. Chickens (from my experience only) seem to be pretty hardy. We had a horrible start to the year.... our hen "Mrs. Perfect" was nicked by a person driving a truck (intentionally running down our flock, one is deceased because of this) and then a few months later she was attacked by a stray dog. Both times she recovered well, although, the second time we had the vet come out and stitched her up. We also brought her to live inside for about 4 weeks to recover. We have since put up electric wire around the property...keeps everyone in and all the unwelcome out!! I hope your rooster recovers well, if he seems to be lethargic and "out of sorts" tomorrow I would urge you at least call a vet and get their input!!