how?

Question
My Female rabbit's kits always seem to die, in about 4-5 days i believe it's my neihbors' cat how do i make her as comfortable as possible?

Answer
If they just die with no wounds then the doe isn't taking care of them.  That may or may not be related to the neighbor's cat.  If you feel she is being disturbed by the cat then you should move her to somewhere where the cat cannot upset her like the garage or a shed.

Make sure she has plenty of nest making material (straw)a nice nesting box and leave the babies alone in the nest for at least a week.  If you are handling them she may not want to take care of them for that reason.

Not all does are meant to be mothers, some just can't do it.  If your purpose is to breed and raise babies, maybe you should consider another doe.

Brenda