Personally to me it sounds more like typical boxer playing...they get rough when the play...goodness knows jetta left enough marks on me at that age...you need to work on time out...placing them on a leash on the door when they get out of hand...yelp if it hurts...and ignore them..it will get better...Jetta barked and growled for attention when excited, nipped my feet and hands etc until she was about 4 or 5 months old...to me this sounds very similar to what we went through and I've heard of other boxer babies doing the same thing...i think it is really a phase at that age mark