We generally do not breed our does until they are about eight months of age. Most does are only bred once a year, occasionally twice. Usually this will depend on the size of their previous litter.
We have had litters range from one to ten. With an average litter size of five or six. The largest successfully raised litter, eight. First TigerLilly, in 2001, then her daughter, Sherri, in 2003. From our experience, Himalayans make fine mothers. We generally put the [wooden] nestbox in on day twenty-six of the pregnancy.

Our does tend to build elaborate nests and pull a lot of fur. Also leave the box in until day thirty-eight, we have gotten live babies as late as that! Some people will remove the box when the babies are about two weeks of age, we prefer to leave it in until the babies begin to be weaned as most does will keep it clean and use it for nursing the babies. If the nestbox has a top or cover on it, the does may use it to get away from the babies occasionally.
We will begin to wean large litters at the age of six weeks into same-sex pairs. Small litters are generally left until eight weeks.
If the babies vary in size, try to find two that are like in size.