I would NEVER leave my bulldogs together unattended and barely let them contact or be close enough to each other to touch when I am there. These are not pack animals! I had a mother and her pick of the litter son and they got into it when he got 5-6 months old and they hated each other the rest of their lives.Had them in my car and someone walked past with a dog and they got excited and ended up turning on each other.I had to drag them out of my car,leash one to the fence,break them apart,take one home and come back and get the other,luckily I knew people on that block to watch over my dog until I returned.Right now I have a little 32 pound female who loves to grab my 55 pound males collar and bite on him.He resists but I know if I left them alone he would get tired of it and probably grab her.I just give them their space.