I've heard about and read about at least a couple of those. Not sure what to make of it yet. On the one hand, I don't want continually sick birds, nor do I want sick birds every time I introduce new ones. Never mind worrying about passively spreading something to other flocks. However, if it is a strain not-unlike chickenpox is in humans where once you have it, you gain an immunity but it remains passive in your body, subdued by your immune system, that seems like something I wouldn't want to cull the whole flock over. And I am keeping them on pasture so they would likely be exposed to it again if is something they picked up here. So.. undecided. SO far, like I said, they all exhibit healthy behaviors and energy from all my observations and those of my far more experienced friend with a Vet Med degree and Vet experience. Hoping for the best and preparing for the worst just in case.