I have put a dog crate inside the run, but I can’t imagine caging the little ones in it all day, they’d have even less space than they already have.
We still have plans to expand their run, but I just purchased two of the wire expandable dog kennel fences that you can set up in different configurations. I’m putting them together into one run (32 square feet) that will function as a tractor and I’ll move it around for them to get some grass and variation. It will also serve as a way to alternate the big girls and the little girls for now.
For us in the next couple of months, fortunately, money is slightly less of an issue than time. So this will hopefully hold us over until we can build something better and more permanent, and by then the babies will be a little bigger as well.