being on their backs for too long disrupts the pressure areas and ability of the air sac in the chicken to function correctly in the respiratory system, since chickens don't have a diaphragm they use air sacs throughout the body to create pressure centers that pull or push "breaths" through the lungs, which do not expand like our but work more like gills on a fish.Oh yeah, They do a turtle impression every so often... none are very good at it! Always The best cockerels and roosters you have of course...Iv actually lost two this year to it. I assume the first fell off while breeding. He was in with hens and was aggressively "courting"... The other was in a "just in case" pen alone. I always keep a few extras... A big storm blew thru, lots of wind and big thunder. I'm guessing he freaked and ended up on his back. Either way he was dead with not a mark on him...Idon't know why they can't lay on their back long and live. Not sure if they die from the stress of being unable to right themselves and feel defenseless. Or if it's a physical issue like lungs filling with fluids. But they are always in the same position....