Feathers are basically composed of structural proteins, the keratins, and are suitable for preparing biodegradable films, which must present low hygroscopicity and water vapor permeability (WVP). To prepare such films, glycerol and sorbitol are the more common plasticizers, but they lead to hygroscopic films. In this work, the influence of polyethylene glycol (PEG) with different molecular weights on the films’ hygrocopicity, solubility, and water vapor permeability was investigated. The water sorption isotherms showed that for all range of a_w investigated in this work the films obtained with PEG400 were more hydrophilic than films obtained with higher molecular weight PEGs. The use of PEG causes an increase in the WVP of chicken feather keratin films (CFK).