I have a group of 3 sows. Chunky, Cookie and Ripple. Cookie is Ripple's mummy and they keep bickering. It isn't all the time but ripple gets left out at meal times and when they are curled up in their house cookie sqeeks at her and pushes her out of the house. It seems as though she is getting picked on by her own mummy. Is this normal or am I in danger of having to split them up?