My pregnant rabbit wont use her nest box!?

My mini lop pedigree BEW is 28 days pregnant with her 1st litter, shes good and healthy and seems ok she is digging, gathering hay and eating and drinking well. The thing is.....she will not make a nest in the nest box i put in for her yesterday, she is trashing it she pulled out the fabric sheet i lined it with and all the straw i put in....Why is she doing this? I put it in the place she chose as i could see she had started to make a nest.....its not nice to see her do this to her nesting box i dont want to upset her or interfere too much but i also want her to have the babys in the nest box as i wont move them and im afraid they will be too cold on the hutch floor. Please give me some advice...i even thought of just taking the nest box out and just letting her do it her way but as i said im in fear her babies my die or ter around the hutch. Any help welcome P.S i have home for the baby bunnies x x x Thanks in advance x x x