Inactive yeast is a by-product of alcohol and the fermentation industry. It is obtained by reproduction of yeast’s fungi on different substrates. Color is light yellow to light gray, odor is characteristic for yeast. It is rich in B vitamins, minerals and amino acids. Dried yeast is also very rich in pro tein and this protein is very good quality, which can be compared with the protein quality of soybean. It binds toxins, it strengthens feathers with vitamin e.