Figure 2.

Effects of O₂ supplementation on the survival rate of Tibetan chickens reared at high altitude. (A) Kaplan-Meier survival curve was used to analyse the survival rate of TBCs in the OSG and NHG, and the log-rank test was used to estimate differences in two groups. The survival rate of the OSG was increased by 10.1% on day 14 compared with the NHG. (B) The number of deaths of Tibetan chicken per day was recorded, then was analyzed using chi-square (χ²). OR: Odds ratio; 95% CI: 95% confidence interval; NHG: natural hypoxia group; OSG: oxygen supplementation group.