Puppies do a lot of play fighting. It's part of their development and a normal way for them to learn limits, as in "this is how hard you can bite before you get in trouble." So if the puppies are just roughhousing with each other -- and even if there's a yelp here and there -- leave them alone. It's when the fighting becomes real that you might need to interfere.
Observe their day-to-day behavior so you can identify who's "the boss." According to All Pets Veterinary Hospital, real rivalry starts as young as 13 weeks. By then, fights start to be about dominance and being the top dog. This is especially common among dogs of the same gender, particularly males. Once you know who's top dog, your job is to enforce that. Top dog gets fed and petted first.
Give each sibling alone time with you. Part of the rivalry among them is probably about who gets to spend time with you. Give each dog equal attention -- the top dog gets the attention first, though -- and love. Don't ignore one and don't show favorites. Each dog is unique and you might naturally have a favorite, but work on giving each dog his time with you.
Feed them separately. While they might have shared a bowl at first, things will probably change as they get older. Even if the fights are not over food, still feed them separately -- just a couple feet apart should be enough. Top dog gets his bowl first.
Set up rules. If you let the dogs run wild and make up their own rules, fights will break up. Instead, establish yourself as leader of the pack early on. Let them know what's acceptable and what's not in terms of behavior. Say "no!" when you see a fight break out or when things get out of control.
- Always stop the fights before they start. There are usually signs that a fight is coming -- eyes locked on the other dog, hair raised, growling -- and that's when you need to intervene. Distract the dogs with a game or a toy as soon as you see those signs.
- Ryan McVay/Photodisc/Getty Images