My chicks range from 5 to 8 weeks. They're still on chick starter feed but are outside pecking away at the ground and grass. The grit bag says to start giving grit at 8 weeks old once they start a heavier grain food. Should I start giving the grit now? Any harm to the youngest chick? And I was planning on feeding them chick starter until 4 months of age; is this correct? Thanks, trusty BYC folks!