I am a first time chicken keeper and have had my 9 chicks for about 8 days. The feed store said they were about a week old when I got them so they are about 2-3 weeks old now (not totally sure). They are in a brooder made from an extra large sterilite bin with a brinsea warmer and an extra heat lamp (when needed). Anyway..yesterday I gave them a small tray with grit on the bottom and cut up salad greens on the top. They seemed to eat about 3/4 of the greens but its hard to tell because they also threw them around. Will this hurt them?