After Rusty's death, I began to notice Penny behaving peculiarly. She seemed to be breathing deeply, standing with her legs wide apart, and bearing down. Sometimes, she'd sit for a while and bear down. Her poos were runny, so she had dirty rear feathers. Oh dear, could she be egg-bound? The symptoms matched. The only peculiarity was that Penny seemed quite alert and was eating and drinking a little; egg-bound birds deteriorate very rapidly. She has lost condition -- always rather a skinny chook, her keel feels like it could cut your hand now.
Last night I gave Penny a nice hot bath, the kind that water-births occur in (only hotter, because chooks have a higher body temperature than we do). She seemed to like it, but the only result was a fart and some green goo which landed on my foot. I left her with a heat pack overnight. While she was no worse this morning, she was no better, either.
The forecast was for 33 C today, and I was worried that she'd die from the added heat stress, so off I went to the vet instead of church. It turns out that Penny has a respiratory infection -- chook pneumonia -- and that the other behaviours are related to keeping her lungs open. I had considered respiratory infection, but discarded it as I couldn't hear her breathing or see any discharge. She looks reasonably well, and we're hopeful she'll pull through. I really don't want to conduct two chook funerals in a week!