The environment in the broiler house is a combination of physical and biological factors generating a complex dynamic system of interactions between birds, the husbandry system, temperature, and the aerial environment. The current field study was conducted in 2 broiler farms located in Upper Egypt to clarify the impact of an indoor climate element
(ambient temperature Ta.C°, relative humidity RH%, and air movement AV m/sec.) on the survivability of microbial load (ML) in indoor air (IA) and on surfaces of abiotic environment components (AC) ( drinkers, feeders, walls, and windows) . As well as on the performance indices PI (feed intake (FI), live body weight (LBW) g/w/bird, feed conversion rate (FCR), and mortality %). The obtained results revealed that, indoor ambient temperatures Ta.C° were the same means value despite of increased SD in farm 2. Higher relative humidity (RH %) was recorded in farm 2 despite of values in both farms still less than 60-70%.
The higher recorded air velocity (AVm/sec) in farm 1 was within the recommended requirement. The bacteria load (BL CFU) from indoor abiotic environment components (AC) in farm 1 was higher than in farm 2 but FL CFU was higher in farm 1. No significant differences were recorded in means value BL CFU between two farms during 7-21 days but reported at 35 days. The mean difference value of BL CFU in farm 1 was significantly correlated within all ages (7-35 days) and in farm 2 between 7, 35 days. The mean difference of FL CFU in farm 1 was significantly increased between 7-35 days and in farm2
between 7, 35 days only. The cumulative means values of indoor air microbial load (IA ML) confirmed a higher mean value of FL CFU was recorded in farm 1, and higher BL CFU in farm 2. Differences were noticed between two farms in performance indices (PI) where increased FI in farm 2, decreased FCR, decreased mortality %. Farm 2 performed well compared with farm 1 indicated by increased FI and improved FCR. A negative correlation was recorded between Ta.C° and all PI in farm 1. Ta.C significantly affected and correlated with both FI in farm 2 and mortality %. RH% negatively correlated with all PI and
significantly correlated with LBW and FCR in farm 1, while in farm 2 RH% was significantly correlated with FI only. Air movement (AV m/sec.) was negatively correlated with all PI and significantly correlated with the mortality rate in farm 1. Conclusion, during winter in Upper Egypt , the two farms didn't reveal significant difference in indoor climate elements but
recorded in indoor air and abiotic components microbial profile which reflected on final performance indices mainly FCR and mortality rate in farm 2.