Mini Lop & Dwarf Lop - failure to breed

Question
HI, We have a mini lop (male) and dwarf lop (female) since 7weeks old or so.  They are only meant to be two weeks apart but the male was a late developer so we wonder if they are further apart in age and are actually brother and sister. The breeder said they were two males but vet informed one was a female.  They have not bred and we are not sure why.  There was one occasion when the female pulled a small amount of hair, but since then, no hair pulling at all.  We thought she might have been pregnant recently as she started acting all weird, and did not want to come inside.  We saw her pulling grass and taking it under the house. But again, no sign of babies.  Are there physical signs (eg breast development) or could one of them be infertile?   They are now twelve months old.

Answer
Firstly, I have to advise against breeding pet quality rabbits,. There is often a reason they are sold as pets rather than as show or breeding quality rabbits. Without knowledge of their background, it is possible that they carry an undesirable hidden trait that can be passed on to their offspring. Seizures, blindness, babies dying shortly after birth, poor mothering instinct (resulting in the mother killing the babies), deformities, and more can all be the result of hidden genetic problems.

However, in answer to your question, there are no signs of being ready to breed. A female rabbit's mammary glands will not get enlarged until after she is pregnant (and generally not even until just before or even just after birth). They do not go through heat cycles like dogs or cats, either. Do not leave the male and female together, though. Firstly, this tends to actually lower the pregnancy rate. Secondly, if she does get pregnant with one litter and the male impregnates her again with another litter, it could be fatal for the babies and/or her. Instead, bring the female to the male's cage to mate.