He is a pitbull and dog agression is totally expected, but he was always fine with other dogs. He's never liked unneutered males but other then that never really had a problem. The dogs were boarded from Sat-Tues and every day they get playtime and walks and the people who work there (who are very pitbull friendly) said Holly was out running with the other dogs and was great but Chapps was really iffy...they actually had to keep him away most of the time. Today my hubby took the doggies for a quick run and a man with his husky came up and asked if our dogs were okay to smell each other, and we said yeah sure, not knowing, and Chapps growled and totally lunged at the dog.
He loves Holly, they are playing right now, couldn't ask for a closer duo, and he loves my SIL's puppy...but maybe he has now turned on most other dogs. He is 16 months and is sexually mature now, so I guess I was hoping for the best, but expecting the worst. Chapps doesn't go to dog parks nor plays with other dogs (except Holly or my SIL's pup) so I don't really have to worry. He's my baby, dog aggressive or not.