hi sorry that you are having problems with your dogs, but also have to agree with the previous 2 posts, ibitches are known to fight till death!! and even more so if litter mates. I know a lady who had 2 bitches and while out walking them 1 day, the bitches just went for each other, she had to run and get help, but when returned one was already dead, i know this is extreme, but you may have to consider rehoming one of them, better to have them both happy in seperate homes, than living with constant tension with each other. sorry again this is probably not want to hear.