They always have enormous litters of kits. They use the nest box every time they kindle. They can be very nervous and may not use the nest box. Rabbits hate greens with a passion. Lots of greens can cause diarrhea in a rabbit.
Greens can stain a rabbit's fur.
All of the above answers. E ating too much food so they get too fat to breed. Drinking too much water which causes a lack of energy. Being bred too many times without any rest between litters. All of the above.