I bought my mixed flock at Rural King from Cackle. I think I have nearly all the breeds figured out and thanks to this site I must admit I am the proud owner of 5 hens out of 21 chicks. (all my barred rocks and all my buff orps are roos! Rats!) I have 5 white chickens that I was thinking could either be white rocks or leghorns. Today I noticed one of the white roos kinda panting, wanting to lay down and drooping his wings. However he still had a pretty good energy level. When I examined him his breast feathers where caked with dirt and very sparse. He is one of the bigger roos. We have had some very rainy weather and the coop got muddy in the open areas a few days ago. Although there was a dry roosting area and clean feeding area they still played out in the muddy section I cleaned him up and isolated him with some electerolytes in his water. My question: Could this be a cornish rock? He doesn't look chuncky enough for a cornish x rock. I've never raised them but thought both tended to have heart and other problems from the heavy breast area. And I also noticed pictures that looked like the breast feathers had gaps that showed skin. Weather here is low 70s with a nice breeze so I'm sure it's not a heat related issue. Sorry it's so long and thanks for your insight!