So we've got now 28 birds in our loft. The most recent additions have been there for almost 2 weeks now. Last night one of our hens was acting really lethargic and sat around all puffed up. She let me walk right up to her and pet her before taking off, which is really unusual for these birds. My dad went out to the coop this morning (it's at his house) to check on the birds and make sure they had enough food and water before heading to work. He found the hen dead and another showing the same symptoms. Any advice on treating the birds, preventing further losses, or what could be causing this? Thanks in advance!