Planning of experiment the experiment. Random complete block (Randomized Complete, Block Design RCBD) trial in broiler chickens 2 weeks of 80 into 4 groups, 4 repeated. It 5 when fully 4 week. So coop counts were 16 from 4 groups 4 repeatedly, the result showed 1 try to supplement the waste yeast มันหมัก in broiler ration level 0 5 10,,, and. 15 percent was divided into 2 experiments. Experiment study of fermentation of cassava 1 ด้วยเชื้อ Saccharomyces cerevisiae can improve the nutritive value better by nutritional composition of cassava residue protein content from 2.8 percent. A 18.08 percent. The fermentation time 30 days, which can be seen that the cassava fermentation at minimal protein up 15.28 percent. Compared with normal cassava residue