Did you check the doe for readiness before you bred her?
Rabbit does don't show estrus like some animals, but they do experience hormonal cycles. About once a month, a doe ripens fresh eggs, and holds them in readiness until hormones triggered by being bred causes her to release them. The doe is at her most fertile right at the time that the eggs first become ready, and will be most likely to breed at that time. If you turn the doe over and press just in front of her vulva, you can expose a bit of the tissue that lines it. If the tissue is bright, cherry red, the doe is at a hormonal peak, and will probably breed readily and conceive a good sized litter. If the color is purplish, the doe is past the peak, her eggs are getting older, and while she may breed, she may have a smaller litter (or none at all). If the color is pale pink, she is at her lowest level hormonally, and it is probably a waste of time to try to breed at that time.
If your doe accepted the buck, her body will produce a hormone that causes her to release eggs. That hormone will reach its peak in about 2 hours. If you breed her again at that time, she will have a second hormone release, resulting in an even higher level of hormone (and hopefully, more eggs being released). That's the theory, anyway.
