The 15–20% of the by-products of meat- and poultry industry – that unsuitable for human consumption – contains keratin. The slaughter technology of poultry produces large amount of poultry feather with 50–70% moisture content. This means more million tons annually worldwide (Williams et al., 1991; Hegedűs et al., 1998). The keratin content of feather can be difficulty digested, so physical, chemical and/or biological pre-treatment is needed in practice, which has to be set according to the utilization method. The microbiological and enzymatic degradation of feather to soluble protein and amino acids is a very favourable and relatively cheap opportunity to produce valuable products of the resulting feather. Our applied treatments were based on the determination of the most effective method, which is able to follow the biodegradation of waste poultry feather.