Very unusual and sad.
Again I'm a rank amateur but Tera was happy as could be in her crate for the first 3 weeks. After that we had to let her out to sit in the window and teach her to play and cuddle. Those first few weeks she was just a milk machine. We knew she needed out the day she grabbed the babies and brought them out with her to scoot them around on the floor. I believe someone reassured me that mother cats often find tight dark places to nurse and care for their babies the first few weeks and to not feel bad about keeping her a crate.I guess she just wanted a smaller and closed in nesting box? I don't know what we are going to do when the kittens are older. Here is to hoping that tomorrow morning the two b/w ones have gained!