Fig. 1

The graph shows the trend of environmental parameters. The horizontal axis represents the time, and the vertical axis represents the environmental parameters. (A) The trend of temperature changes inside and outside the duck house. Tmax-in and Tmin-in mean maximum and minimum temperature in the duck house, respectively. Tmax-out and Tmin-out mean maximum and minimum temperatures outside the duck house. (B) The trend of ammonia concentration in three positions in the duck house. Specifically, the ammonia concentration of 0 at 14, 15, and 16 days of duck age was due to the ventilation of the duck house. (C) The trend of temperature changes in three positions in the duck house from 14 to 47 days of age. (D) The trend of temperature change in the duck house for 24 h on different days. (E) The trend of relative humidity changes in three positions in the duck house from 14 to 47 days of age. (F) The trend of relative humidity changes in the duck house for 24 h on different days