Thanks for the info...the thing is that he's been on his lead by himself when he's broken his collars. He's okay when we're out there, but sometimes I just put him on the lead to go to the bathroom for a few minutes. This last time, my neighbor's dog was outside and he wanted to go see him

. He's a mixed breed, supposedly australian cattle dog and hound mix. He's VERY strong...good dog too. Just gets a little excited sometimes.