how long do you put a male in a females rabbit cage

Question
My rabbit Bun-Bun (i think)killed his 2 female girlfriends. They lived together, and i know.. WHAT WAS I THINKING!? I have a new female bunny now, and i really need to know how long you put the male into the females cage. and he does not smell her cage because he used to live in it. My friend uses wood shaving's,or should i use hay? or both? please please help me because i have allready lost 2 rabbits!

thankyou so much for all your help,really i needed help!

Answer
hi hayley -keep them seperated until you want to mate them -then put the doe in with the buck not the other way round.mating should take place immediately if she is reseptive then remove her straight away or they will fight.wood shavings or hay is ok -i use sawdust.
dave