My speckled sussex chicks are now 4 weeks old. They have nearly all their feathers in and are in room temperature in their brooder. Does their feed need to be advanced at some point? And if so to what? Also is it okay to give them grit that has the oyster shell mixed into it at this age or should I stick with chick grit? The feed store I went to this afternoon only had one kind of grit. I thought Iʻd read somewhere that they shouldnʻt have too much calcium at this age. If you have any information, Iʻd appreciate it. Iʻm a real newbie at this.