i have noticed the past few days that one of my chickens has not been very active and just kind of sits on the ground and is lathargic. she won't even fly up to the roost at night. i went out to check on her and she is blown up like a ballon. her back end is so blown up and firm. she is also having difficulty breathing. it sounds like there is fluid in her lungs. i had to put her out of her missery. what do you think was the problem? i suspect worms. would this bee the case?