Evaluation and association of laying hen performance, environmental conditions and gas concentrations in barn housing system

Various environmental, constructional, and human-related factors affect overall eggs production. The egg poultry production has been analysed in barn housing system depending on birds' life cycle time and environmental conditions (carbon dioxide concentration, outdoor and indoor temperature, indoor relative humidity). Within the present research study, the data provided by the Baltic poultry industry company has been analysed. Outside temperature, environmental conditions, carbon dioxide (CO2) and ammonia (NH3) concentrations were continuously monitored in two-storey tunnel-ventilated layer house from January to June 2021. CO2 and NH3 gas concentrations were higher during the winter (p < .05). The outdoor temperature during investigation was in range from −27 °C to +13 °C. The indoor temperature and CO2 concentration were higher on the 2nd storey (p < .05) and influenced by outdoor temperature. The relationships between CO2 gas concentrations and environmental conditions (indoor and outdoor temperature, indoor relative humidity) have been detected in the research. The indoor relative humidity tended to be negatively correlated with indoor temperature (rxy = −0.59) and positively correlated with CO2 concentration (rxy = 0.68, rxy = 0.54); the indoor temperature increased, then relative humidity and CO2 decreased. Results showed that the hen-day egg production and feed conversion ratio (FCR) depend on the hen age (p < .05) and temperature (p < .05), and not depend on the CO2 levels. If the CO2 and NH3 levels are in acceptable range, gases will not influence hen performance