1 of my chickens threw up when my daughter was watching them the other day . When I checked her tonight she was very swollen in the cest and she opens her mouth over and over again , like she is gasping in slow motion I also noticed that her beak may have some slime on it . When I checked the rest of the flock I found 1 other with same swollen chest just not as bad. When I felt it , it feels like fluid not ferm or hard just soft and squishy . What is it and what can I do, the rest of flock look and acting great no problems. both are about 12 weeks old , and are the same mix , should I get them away from the rest of my flock , help please.