GREAT JOB ON THE RESCUE LORI!!!!! You did the right thing! If you had not gotten them now then chances of catching them later would be darn near impossible. At this stage you can tame them and hopefully find them homes where they will be loved. If you had left them with mom they would have been feral and chances are they wouldn't have survived very long at all. Not to mention they would have eventually made you lots more babies! I know its sad to take them away from momma and that is heart breaking. Hopefully you can get them all together again.
The small cage in a larger cage is a good idea. At least if you get her then you can get her spayed and put her back out once the kittens are weaned.

I agree with Kim that those babies are at least four to five weks old. You need to offer them mush because they are going to require more than just KMR at this point. Mash some canned food and mix it with some KMR and see if they will eat. I have a feeling they will! I would still supplement with bottles several times a day but I would get them eating soon.

They are absolutely ADORABLE! It looks like Tennessee is having the same run as Kentucky....black, black/wht, and gray have been in abundance this year!