In the modern intensive production environment, multiple broiler flocks are commonly raised on a single batch of litter where day-old chickens are placed directly on used litter (Volkova et al., 2009). Litter is mainly composed of the bedding materials, feather, manure, the spilt feed and microbiota. Bolan et al. (2010) stated that microbial populations in poultry litter can exceed 1010 cells per g of litter and gram positive bacteria account for almost 90% of the microbial diversity. It is suggested that poultry litter provides stable environment for newly-placed chickens for colonizing adult-type microbiota (Torok et al., 2009;