One of our hens has become very fat recently. She waddles when she walks and is slow moving. She also reacts more slowly to food. The comb is pale pink and has flopped to one side. She sometimes looks like she's straining to lay an egg or poo, sits and closes her eyes. She is about 3 years old. This has been for maybe 4-5 days. We gave them some calcium in the water but she didn't drink much. Does anyone know what is wrong with her? Another chicken is also sick, sitting very still by herself not eating much. That has happened before to us and she recovered, but I'm worried she won't be as lucky this time. Help!