New sick chicken

Okay so on the plus side, my previously posted chicken has made a full recovery and is back to normal. However now my Americuna is sick? This is a different illness it seems. Her stomach and lower area is extremely bloated and puffed up, like she's full of water or something. She's standing like a penguin. Has anyone had this issue??? This is only happening in the last two days, she has been fine up until the other day so it has rapidly developed. Please help