In this experiment the authors re-evaluated the digestibility of heat-dried brewery's activated sludge with cocks fitted with artificial anuses by feeding the diet containing the sludge at 20% level which was two times as much as the amount used in the preceding experiment and investigated the availability of the sludge as a protein source of feed for laying hens by feeding experiment. For the increasing of the amount of sludge, it became possible to estimate the digestibility of crude fat contained only 0.8% in the sludge. The results obtained were as follows: Digestibilities of the sludge were 70.2% of crude protein, 87.3% of crude fat, 64.2% of nitrogen-free extract and 55.3% of crude fibre, and estimated digestible crude protein and total digestible nutrients were 26.4 and 47.1% respectively. No detrimental effect was observed on the egg production in the laying hen receiving the diet containing the sludge at 5% level. It also had similar tendency on the quality of eggs laid. As the results of this experiment the authors suggest that within 5% ingredient it is possible to use the heat-dried brewery's activated sludge as protein source of feed for laying hens.