Just for information for everyone....rabbits (along with many small mammals) do not have an estrus (heat) cycle. They are "induced ovulators" which means they become fertile shortly after a male mounts her. In reality, this means thedoes are technically "in heat" nearly all the time if she isn't pregnant. Since in nature rabbits are quite low on the food chain, this helps assure there are sufficient births to maintain population. In certain parts of the US, cottontails deliver a litter of babies every 28 days or so all year so that means each doe can birth somewhere closeto 60 babies each year....approx 10% survive to breeding age. The doe can become pregnant againshortly after she delivers a litter due to the special design of the uterus. The hormones in many does that are not used to breed can become so intense they go thru a "false pregnancy" and will do everything except deliver kits. Interesting to watch...stressful on the rabbit.
Randy