“…In none of the six hatches was hatchability of fertile eggs below 70%, whereas, Lindstrom et al (1949), Olcese and co-workers (1950), Couch and associates (1950), and Carver and McGinnis (1950) have presented evidence showing that the hatchability of eggs produced by birds which received an all-vegetable protein diet and did not have access to their feces decreased rapidly and in most instances was below 50% within four weeks. The amount of vitamin B i2 activity, as indicated by hatchability, observed in the present trial with rations containing no added vitamin B 12 was unexpectedly high in view of the results of Kennard et al (1948), who obtained only a 32% hatch on shavings litter changed at two-week intervals as compared with 78% on built-up litter. In the present trial, over 70% hatchability was obtained after 168 days on wheat-straw litter changed at weekly intervals.…”