You've received some good information and opinions.
I wanted to mention grit that I forgot to include in my first post.
Years ago I didn't bother giving grit to chicks because I only fed starter feed and I figured the grains in it are already ground. However, when I started offering chick grit (#1 size), they seemed ravenous for it.
That size is only beneficial for the first 3 or 4 weeks because it is small enough that it will pass right through the gizzard without lodging there and aiding in grinding.
After that one should move to #2 grit till 7 weeks and then on to adult grit (#3). If you can't get all 3 sizes, adult grit can be used a little sooner since there are usually some smaller bits in it.
http://www.tccmaterials.com/product.cfm?id=605
It does help to develop the gizzard. I now sprinkle a bit on feed the first few days and thereafter, I offer it in a separate container.
A couple years ago, I sold some chicks to a local friend. She ended up getting more cocks than she wanted so I traded a pullet for it. When I butchered the cockerel at the same time as it's brothers from the same hatch that I raised, my birds' gizzards were almost twice the size of hers.
If one feeds anything besides feed, grit is essential - especially for grains/seeds and greens.
