I wasn't sure where to post this - issues, meat birds, solutions... so I figured the moderators can move it if I did bad. Just thought I'd summarize and share a recent experience we had with attempting to brood Cornish Cross broilers, heritage red broilers and several species of egg layers in a shared environment. They all "met" as day old chicks and all established their pecking order together. The theory was - sure the Cornish X will get bigger faster - but they are going to pasture at 3 weeks so they will only be about 2x in size over the egg layers and about 1.5x over the red broilers. Since we have LOTS of space in the brooder building and have done Cornish X's a bunch of times before... it all made sense on paper. It worked great for the first 2 weeks actually - no issues at all. Simple to water and distribute food to. Plenty of space per bird. We then had a sudden heat spike which induced stress simply by virtue of making the birds hot and bothered. Attached is a link that includes all the thoughts, observations and learnings - http://www.chickenthistlefarm.com/2010/06/chicken-stress.html The summary is - I wouldn't recommend the co-habitation route in a shared brooder for chicks IF it includes the Cornish X variety and ANYONE else. The Cornish X are just so different they just become targets. Red broilers (heritage) and laying hens - they seem to get along just fine. This site is a great resource so I figured we should give something good back!