FT- I have a RIR that I am sure is laying and the other 2 are pretty identical Red Stars. I have not ever checked their vents. It doesn't seem like its gonna be as easy as you make it sound, but I'll attempt it. As far as the light cycle, they do have 14 hours of light every day. Their food is a Layena layer crumble. The RIR's shell is really hard, but the one Red Star that is laying has a very thin shell that breaks easily. I haven't seen any evidence that the "non-layer" is passing non-shelled eggs either. So, let's go on the weak shelled eggs for a second. If I add foods to provide more calcium and protein, will it effect the RIR that already has a very strong shell?