Rabbit Litters?

Hello, my rabbit had babies March 25. She is due again on May 13. The first litter is 39 days today (5-2-08). When can I put her first litter in a seperate cage? They eat and drink perfectly fine. Right now I have them in a seperate cage because the mom is pulling fur from the babies and they are getting scabs. She is gathering hay and making a nest in the nest box part of her hutch. Is this normal for a doe to do about 10 or 11 days before the birth? RABBIT EXPERTS ONLY PLEASE. Lol, thanks!