Polyester. Hen Protector This hen reflective vest protects the back and wings of the hen during mating, and is not injured by the rooster's nails or chicken pecks during mating, thereby improving fecundity. Feather Recovery - This wing back protector protects birds with pecked feathers, promoting healing and feather regrowth. The hen reflective undershirt will also keep hens warm during the colder months. Lightweight And Soft - The poultry protector is made of waterproof polyester fabric, breathable and lightweight, with an elastic band and plenty of stretch to provide a comfortable fit for your pet. Safety & Visibility - The bright colors combined with the reflective stripes have a reflective effect at night, making your pet easily noticed and making your pet safer and helping to avoid accidents.