My two kitten boys are 11 weeks old. This morning very early at 3 am we woke up to an awful noise and found out it was the kittens growling at each other and showing aggressive displays. It hadn't progressed into fighting but they wouldn't stop yowling at each other. We had to separate them in different rooms to get any sleep. The only thing different was that I bathed both boys yesterday and the shampoo I use has fragrance. In the morning they were both just fine like nothing happened. Is this normal?