Catch weed
Chickweed
Yes, give them a few each day while providing a little chick grit when they're 2 weeks+ old. Also, give them wild herbs and weeds like: chickweed, catch weed, chopped parsley (if you grow it or buy at the store), scrambled eggs (dry no butter) and wild oxalis leaves in...
My 8 chicks are about 2 weeks old (March 1st), waiting to see if my BR is a pullet or cockerel. I have 3 red sex links and 4 black sex links as well (one is slightly different coloring--we'll see). Growing fast, very active and wanting to fly, I don't remember my other chicks being so active...