Pen oxygen concentration and pulmonary hypertension-induced right ventricular failure and ascites in meat-type chickens at low altitude.

Percentage O2 and CO2 were measured in the air in environmentally controlled commercial poultry pens (altitude approximately 300 m) containing broiler or roaster chickens 14 to 56 days of age. Outside air (mean of 10 samples) measured 20.85% O2 and 0.041% CO2. Air in the pens had significantly lower O2 and higher CO2 than outside air; however, air in 25 pens with a high incidence of ascites (mean 20.50% O2, 0.264% CO2) was not different from the air in 25 pens with a low incidence of ascites (mean 20.49% O2, 0.319% CO2). The lowest pen O2 was 20.20%, which would not cause reduced hemoglobin saturation (percent oxygen) of the arterial blood of normal chickens.