In order to investigate the effects of environmental temperature on egg production, food intake and water consumption in laying White Leghorns, this experiment was performed. Fifteen hens (10 of them were 1 year old hens, 5 were 2 years old hens) were kept in the temperature room from 25 to 35°C changing by 2.5°C at each interval during 10-15 days. The results obtained were as follows;
1) The higher the temperature becomes, the lesser food intake was observed. The decreasing rate was 1.6% per Centigrade rise of environmental temperature from 25°C to 35°C. Water consumption increased with the rise of temperature. Each ratio of water consumed per one g of food intake was about 2 times at 32.5°C, and about 3 times at 35°C as much as that at 25°C.
2) Egg production rate was lowest at 35°C, being 73%. Daily egg production was also lowest at 35°C, but food efficiency for egg production, was highest at 35°C, being 61%.
3) Excluding abnormal eggs, net efficiency for egg production was highest at 32.5°C, being 53%, but being 42% at 35°C. Appearing rate of abnormal eggs was attained to 31% at 35°C. Comparing 25°C with 32.5°C, the latter temperature regime had by 15% higher food converting efficiency. The reason for the highest food converting rate for egg production at 32.5°C was discussed.