My chicks are a little over a week old and I was wondering how soon they could try other foods? I have some wheat grass and alfalfa to sprout for them. I also found lots of earthworms while I was digging in the garden the other day. Could they try these things? I read if/when you start feeding things other than chick starter that they also need gravel. I have some parakeet gravel on hand. Will that be sufficient for them?