I had 15 birds die this weekend. They all had the same symptom gaping vents where you could see their organs. I had another one die today. I don't see maggots. I also have one with a yellowish behind. Many are losing their feathers under their wings and near their vent. Can anyone help? Edited to add, these are 7 week old Ranger Broilers. They are being raised in a portable pen. They are fed organic feed.