gardenrn, thanks for the info!
They are so BIG! Actually, we only have two chickens now. One was killed by an unknown predator. Now we have them fenced with an electric line running around the outside. The other was born with some kind of digestive problem and died because of it. The last two (one boy, one girl) seem quite healthy. They are close to full grown, I think? The rooster is just starting to crow.
I switched from starter to laying feed, and now they have dirty bottoms, I don't know if you could say their poop is runnier than normal, but somethings up. Maybe I need to get the growing feed instead. It's so hot here, too, we put some shade cloth over the pen and I am hoping that will help them out.
I would love to see pictures of your pen. We aren't ready for anything that advanced yet, but one day....