What purpose are you breeding these rabbits for? Let me warn that it is very hard to find homes for mixed breed or pet quality rabbits, as there is a pretty large supply but not too much demand. If you were planning to sell the babies as pets you might want to reconsider breeding. When breeding, you need to make sure you bring the doe the buck's cage and leave them together only long enough to breed (the male 'falls off' when he's done), then remove them promptly or else the doe could attack and severely injure the buck... she might attempt that anyway if she isn't in season. There are some good websites and books out there on breeding rabbits, it's really something that you need to go in with more information than what you can get out of individual questions like this.