My meat birds have been dying since I got them Thursday. I talked to my friend's dad who's raised meaties his whole life and he said based on their symptoms they were having heart attacks from growing too quickly. He suggested I start taking their food away overnight. I took their food away when I got home and so far everyone is alive and doing well. My layer chicks, not so much. I think they have some sort of respiratory infection. They all the sudden grow weak, I find them laying on their sides barely breathing. Their crops are always empty when they get to this point and it happens very suddenly. They silently gasp for air (unsuccessfully) and convulse and die, leaving a weird mucus in their throat. They all look fine, but I've had 3 die. Like I said, it happens very suddenly. I'm only able to pick them out about an hour before they die, sometimes less. Does ANYONE have ideas? I'm about to put duramycin 10 powder in their water. I don't know what else to do. They are only 3-31/2 days old. What in the world could have infected them this early?