I have a hen, Betty who is sick. She started off just seeming a bit depressed, and then one day she stopped eating and looked very droopy. I lost another hen about a month before, with similar symptoms, so I decided to take Betty to the vet. She started vomiting quite large amounts of watery substance with bits of brown. It wasn't smelly. The vet thought she was very sick and would probably die, but said we could try antibiotics. After the first dose, she perked up almost immediately and within 2 days was eating and even laid an egg. She is now 5 days into the antibiotics, but has not quite recovered to her normal self. She still seems depressed and quite lethargic - she will go out and scratch and eat a bit, but then seems to need a rest. Her comb has gone very pale over the last 2 days (it was still dark red when she was first ill). I also think she may be constipated - she is only doing one or two small poos in the night. She is drinking a lot of water. Could there be something wrong with her that is making her prone to infection? Is there anything else I can do? The vet said she felt an unusual lump near her vent as well, and that she was quite underweight.