When we first started breeding our rabbits, Lydia and I would put the nesting boxes in seven to ten days before the does were due to kindle. (We then learned that if a nesting box is put into the cage too early, the doe will use it as a litter box.) I read in a book that if a rabbit builds her nest on the 18th day, that she is not pregnant--that it is a false pregnancy. So I was sad when Snowball started building her nest on the 18th day. We debated whether to just breed her again, but in the end we decided against it.
We were very glad that we had not tried to re-breed her when we found eleven kits in her nesting box.
We have found that Snowball will start building her nest as soon as the nesting box is put into her cage. She is our over-achiever.
On the other hand, Tootsie and her daughter Sage were/are our multi-taskers. (My mom wrote that they were/are slackers. That was not nice. At all.) They basically build their nests while kindling their litters. Seems a little amazing. (My mom said reckless. That wasn't very nice, either.)