8 week olds not eating

I just got three 8 week old pullets that I put in with my bantam D'Uccle roo. (He had been boss roo, but the two 9 month old roosters out grew and out hormoned him... he now has a new condo.)

The problem is that they have been COMPLETELY free ranged, and brought up by momma Chicken. They don't seem to know what a feeder is! The three babies are scratching and pecking and trying to catch flies, but not the feed. I tossed some feed out into the run, and they pecked lightly, but not really eating. I have a mealworm "farm" and tossed out a cup of worms and beetles as well.

Slash the roo, bless his heart, is a wonderful rooster. He has spent the last 2 days finding and clucking for his girls to come and eat his goodies, but they are ignoring him! He just gets louder and louder, but they aren't going for it.

I did show them how to get a drink from the nipple waterer, but how do I get them to eat? It is really hot, and I'm sure they are nervous with the new environment. Could this be why?