I started out with 13 RIR hens and 2 RIR roosters (all day-old chicks when I got them) in the last week of October, so they're about 8 weeks old now and fully feathered out. They've lived in a 4x4x4 brooder (indoors) since then. I lost one hen to pasty butt early on, and they were fine after that. Until 2 weeks ago. I've now had a hen and one rooster (the less dominant one) die for no apparent reason. It's not predator attacks, there is no blood in their stool that I can see, and they're on a diet of sprouted barley/wheat/sunflowers and crumbles. I now have another hen acting sick, so I quarantined her. Her feathers are puffed out like a puffer fish, she's unsteady, unwilling to walk or even flap, and she fell over when I gently pet her earlier. I stood her back up, she looked around, then pecked into her water. I'm at a loss. I know they're crowded, but I don't have their chicken tractor finished yet, so I can't relocate them just yet. We DO have a lot of hawks (and even a bald eagle), a couple cats and a dog that would be a hazard to them if I let them free-range, too. Any thoughts? Anything to look for?