I have no idea what I'm dealing with. I have a flock of mixed breed laying hens here that have something very bad. I have had them for one year with no signs of illness. I practice very strict bio-security so I have no idea how they got this. I have never seen an illness here. Symptoms are swollen face and having a hard time breathing then they drop dead within 24 hours. I have the ones that are healthy on tylan in the water but as soon as ones get sick I move them to a quarantine pen. What could kill something so quickly? I will be sending one of the dead ones in to the lab but I need to know NOW what this is. Ideas?