Hi I am new to raising chickens and I'm not sure about how much variety I should be giving them. As I live next to a dog park and dogs can get into my yard so the girls can't free range. I give them green leafy veg nearly every day or some grass pulled out of the garden. There main food is growing feed which is always in their run but they also get some scratch mix in the afternoon. Can you feed them too much? I have also heard they should have some shell grit. Is this mixed in their food or just given on its own? I have 1x light Sussex, 1x australorp (both hatched sept 2012) and 2xRIR bantams (hatched august 2012. Unfortunately no eggs yet.