EU COUNCIL DIRECTIVE 2007/43/EC of 28 June 2007 lays down the basic rules for the protection of chickens kept for meat production (broilers).
According to the Directive, the concentration of ammonia in livestock housing must not exceed 20ppm and that of carbon dioxide must not exceed 3000ppm for livestock farms with a density of more than 33 kg/sqm.
The legislation also considers other parameters. For example, the indoor temperature should not exceed the outdoor temperature by more than 3°C when the latter is below 30°C in the shade; and the average relative humidity should not exceed 70% in 48 hours when the outdoor temperature is below 10°C and the lighting is equal to 20 lux.
There are many environmental parameters that the farmer must keep under control and balance with productivity and operating costs (e.g. heating, ventilation, extraction). Optimising them can give farmers a great productive advantage.