I have never even thought about this, never had an issue with any puppy. He is excellent indoors however outside he is a terror on four legs. He loves people all ages and dogs too. When he notices a person he immediately jumps up at them, whines as if I am beating him I have to for warn everyone as he is teething still. He understands so much I really do not want to muzzle him I find that cruel. Any suggestions this is Moses mommy again. His testronic level is extremely high not due to be neutered until April won't allow thank you in advance