When a rabbit is getting ready to go into labor, she gets her nest ready. She will pick up straw and hay in a realatively straight pile and rearrange how they lay in the nest box. This is called Making Bones, I think because it looks like a dog holding a bone.
I put the nest box and straw into Meg's cage tonight because she should be kindling in the next few days (at least according to my calendar.) Immediately she began making bones, so we're excited and anxious to see if the "3rd times a charm" is true. Updates soon!