I have two 14-week-old standard poodle littermates, one male, one female that we brought home at 8 weeks. I just found out about littermate syndrome, and I'm worried we made a huge mistake, but I don't feel like I can rehome a pup at this point as the family is too attached. I just ordered a second crate so I could crate them separately, and I'm walking them separately and together. I have them signed up for separate puppy classes. They're picking up on commands easily and pretty much came potty trained. My main concern is that I don't want them to develop aggression. Is it okay to let them bite each other when they play? I stop it when it escalates, but I can't seem to get them to stop the play biting. They don't yelp like it hurts or anything. I'm just wondering if this is normal, safe play, or if I shouldn't allow it.