Lilac and shadow have been living together since nov last year,last night for no reason at up all they started fighting,i could here lots of noise in the bunny room i went in and fur was flying everywhere i had to split them up and put one in each side of the pen,i let them back together and they started again,so i took them out cleaned the whole pen out and put them back in, and they have been fine since any ideas what caused this?