Looks like my father in law brought some infected chicks to my flock and now I'm paying the price. Its looking like MG. 14 birds in my original flock. About 5-7days after the chicks arrived, I noticed the gurgling, gasping for air, nasal discharge in only one pullet. After isolating that one, I realized all were showing some lethargic behavior and soon all were gurgling and refusing feed. I did notice bloody looking tissue in the poop. Most have the green diarrhea. All are on corrid, this is day 5. All are on Tylan 50, this is day 5-6. Some days only 2-4 are gurgling, but most days no one wants to eat or move around much. I'm worried about 2 worse off ones that I'm now having to feed by syringe daily. There's no major improvements in any one. My heart is so broken over my beloved birds. When is too long for Tylan? Any advice appreciated. Ive since lost 2 since this began. One had MASSIVE liver with white speckles all over it.