It is common to see the kittens move sometimes for 2 weeks before delivery.
You say you see milk? If milk comes out when you squeeze she could be close, or if she has had kittens before, that doesn't mean anything.. haha..
I would look for a lengthening of the vulva, You will see it gradually relax and open up, there will be discharge at some point, anywhere from 2 days to hours before birth.
Lots of good advice already! Personally I only let the cat eat a few placenta's.. it can cause diarrhea.
If she was feral I would try and leave her alone as much as possible, and try not to pick up or move the babies much, it can stress her out and cause her to move the kittens.
When she is nursing continue to feed her like others have said to feed her while she is pregnant.. let her be the guide to how much she needs.
We have a rule here about picking up kittens here, once a day only until they open their eyes, anywhere from 7-15 days old..
Please weigh them and keep and eye on them until they are 'out of the woods' Good luck!! and in about 4 weeks... start wearing shoes at all times, that is if you like your toes!!!!! lol