I am at my wits end with my 15 week old Border Collies biting. I have raised other Border Collie puppies and none were this bad. I am nearly ready to give this dog up. My children have to be completely segregated from the dog. They cannot walk anywhere in the house without him jumping all over them and biting. They are starting to fear him. The dog gets 2 walks daily with lots of outdoor and indoor playtime. I doubt exercise is the problem. I have tried ignoring the biting, making high pitched yips, dousing ourselves in anti-chew spray, waving a vinegar soaked rag in his face, and saying leave it. The problem is only getting worse. We try positive reinforcement when he chews his toys and when he only sniffs or licks. Literally nothing works. I do not want to permanently muzzle him, but I may not have a choice. We end up leaving him outside by himself often just so our kids can have some peace. I know this is probably wrong too, but we are out of things to do. I am desperate for something that works.