I bred them to what we were told was a new Zealand but I think he's a California red buck.
The Californian rabbit is a color known as Himalayan or Pointed White. There is no recognized breed called a California red.
Californian rabbit
New Zealands come in Red, but unless the breeder is trying to keep his colors and animals showable, the color can degrade over generations.
New Zealand Red
If your girls have gone over 35 days and done nothing, chances are that they have missed. I have heard of rabbits going as long as 40-some days, but that's rare. A rabbit doe can do a thing called 'delayed implantation,' where she carries viable embryos but they don't implant and grow until a later date (the longest suspected case being about 6 months!), but that is a rare event.
Whatever some may lead you to think, a non-pregnant rabbit doe is not always receptive. Rabbits experience hormonal highs and lows, and a doe that is at a hormonal low probably won't breed, or if she does, is pretty likely to miss. Before trying to breed a doe, turn her over, and check the color of the inside of her vulva. The best color would be bright, cherry red. That signals a doe at a hormonal peak; she has freshly ripened eggs and will most likely breed and kindle a good sized litter. A doe that is showing a purplish color has passed the peak, while she may breed, her eggs have been held for a while and she is likely to have a smaller litter. A doe that shows a light pink is at a hormonal low, and most likely won't breed.
Rabbits may not breed for a variety of reasons, heat stress being one of them. At this time of year, that would be my number-1 suspect with rabbits that show no interest in breeding. It also isn't unusual for a buck to become temporarily sterile during hot weather.
Age definitely plays a role in rabbit fertility; how old are these rabbits?
