xmlns:atom="http://www.w3.org/2005/Atom" xmlns:atom="http://www.w3.org/2005/Atom"
the concentration of ammonia (NH3) does not exceed 20 ppm and the concentration of carbon dioxide (CO2) does not exceed 3 000 ppm measured at the level of the chickens’ heads;
the inside temperature, when the outside temperature measured in the shade exceeds 30 °C, does not exceed this outside temperature by more than 3 °C;
the average relative humidity measured inside the house during 48 hours does not exceed 70 % when the outside temperature is below 10 °C.