Why this warning from McMurray:

[alcmaeon]

"These birds are not recommended for raising at altitudes above 5000 feet.

THis is the last line in the text for McMurray Jumbo Cornish X Rocks,
http://www.mcmurrayhatchery.com/product/jumbo_cornish_x_rocks.html

I was just wondering what effect altitude has on this chicken breed.

 

[4H kids and mom]

That is most likely because the Cornish Rocks grow so much faster than normal chickens, that they are already at risk for heart problems, and the altitude would increase the pressure on their hearts, leading to early deaths.

 

[silkiechicken]

Yeah, I raise a few of thoes every year and even at just 500ft... basically sea level, they breathe really hard. At such high altitudes they would probally die due to a lack of oxygen the first time they were spooked!

 

[Wes in Tx]

Not enough Oxygen.