So happy to see a shell-less egg!

Yesterday morning when DH and I went to let chickens out, we saw broken egg inside the coop, but no shell. We just figured somebody popped one out while on the roost or knocked it out of the nesting box. Who knows? This afternoon, when checking the nesting box, I found a perfect little pullet sized shell-less egg. I think my freeloading 26 week old EE is finally starting to lay. It's been raining and really gross outside today, so they've all been in the coop all day. Leopard, the laying suspect, has been on the roost all day. She looks so sad and sleepy. Rainy day blues? Could it have something to do with the shell-less eggs? We do keep oyster shell out at all times too. Also, random, but any idea how often OEG bantams lay? We have 2 that have been here since Sunday and haven't gotten a single egg. I'm pretty sure they are laying age.