Wijaya, et al.. PENGARUH SUPLEMENTASI HIDROLISAT BULU AYAM DAN MINERAL ORGANIK UNTUK MENINGKATKAN KECERNAAN PROTEIN KASAR PADA RANSUM SAPI Effect of Supplementation of Hydrolyzate Chicken Feather and Organic Minerals to Improve Digestibility of Crude Fiber and Crude Protein in Cattle Rations.