hello all, so i am going to give you the whole story, about a month ago my buddy asked me to watch his pitbull meatball for him, she is two months younger than my dog carter, also a pitbull (male), but she is significantly bigger than carter, id say almost 30-40% bigger. Before I let her over we had the meet and play around just to see if they got along, and everything was fine. I have had her for about 3 weeks and they were adorable together, we even called them boyfriend and girlfriend because they were so cute. This was up until three days ago. During the day they got into a little fight that we were able to break up by just raising our voice. We didn't think anything of it and this might of been where I messed up and didn't read this as a signal of anything. Regardless, later that night they got into a bigger fight in which they both were hurt a little and my brother and I were hurt trying to separate them. The fought broke out after I started to feed them, we have a routine where I have them sit, I fill there bowls, then I give them a command that they can eat. A I sat them down meatball just went after carter. It was a good two minutes before we could separate them. Since then they have been separated and have had no contact but I just want to pick the brains of the people here and see why you think this would happen. A side note that I thought of too was that she was on her period. She has been on it for a few weeks and stopped bleeding last week. We are just really curious and concerned why she would attack him like that and why they would fight after being friendly for so long. Any ideas or suggestions or questions please feel free. I am very interested in learning more about this. Thanks all.