Three experiments were conducted with commercial chicks of a certain stock hatched in different month. The main objective of these experiments is to investigate the effect of photoperiodism on maturity and productivity of laying birds.
In the first experiment, chicks hatched in February, April, June, August, October and December, 1965 were used. Until 120 days of age chicks were reared under natural daylength and then, after 121 day, given 14 hours of lighting.
In the second experiment, chicks hatched in April, July, October, 1967 and January, 1968 were used. Until 154 days of age chicks were reared under natural daylength and then, after 155 day, given increment of 15 minutes a week to reach a maximun of 16 hours a day and maintained throughout the laying period.
In the third experiment, chicks hatched in April, June, August, October, December, 1969 and February, 1970 were used. Until 120 days of age, chicks were reared under natural daylength, and then, after 121 day, given 15 hours of lighting.
The results obtained in the three experiments were:
1) In spite of chicks were given the constant or step up lighting that is longer than the then natural daylight after 121 or 155 days of age, the maturity of chicks was strongly influenced by the change of natural daylength before the lighting control.
Consequently, the chicks hatched in both autumn (October) and winter (December, January and February) matured earlist and were followed by those hatched in spring (April), and then those hatched in summer (June, July and August).
2) In all three experiments the chicks hatched both autumn and winter produced higher percent on hen-day egg production over the laying period until 690 days of age.
3) The coefficient of correlation between age of first egg and egg production of survivors in each hatching month group of each experiment was calculated for three period i. e., from the age of first egg to 510 days of age, to 570 days of age and to 690 days of age. The coefficient of correlation for each hatching month group showed negative value except for the period to 510 days of chicks hatched in June in the first experiment. When the hatching month groups were pooled in each experiment, all the correlation coefficient were negative value and statistically significant.
4) No definite tendency as to the relation between mortality and the age matured was observed.

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Fayoumi, 2 strains of White Leghorn originated from same population and separated by the existence of sex-linked dwarf gene (dw), that is, WL-F-dw and WL-F-DW were used for studying the breed difference in tolerance against high protein diet.
At one week of age, chicks of each breed were divided into 3 groups, and the first group was fed a diet containing 20% of crude protein, the second group a diet of 40% crude protein and the third group a diet of 70% crude protein.
Many articular gout bird were observed in Fayoumi fed high protein diet. Percent incidence of gout in 40% protein diet group was 25.9 percent and that in 70% protein diet group was 47.8 percent. None of gout birds was observed in other groups.
High incidence of inanition death in WL-F-dw fed 70% protein diet was observed.
Male chicks of each breed on practical feeding were divided into 2 groups at 7 weeks of age. One group was fed a diet containing 17% of crude protein and the other group was fed the diet of 70% protein for one week, and plasma uric acid was measured.
Plasma uric acid level of Fayoumi chicks was always higher than that of the other breeds.
Considering gout and inanition induced by feeding high protein diet as the index of tolerance against high protein diet, Fayoumi seems to be the most susceptible and WL-F-DW be the most resistant high protein diet among the 3 breeds tested.

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Five days old chicks of Fayoumi were fed a diet of 40% of crude protein to 14 days of age for screening the abnormality induced high protein diet feeding.
After screening, chicks were divided into two groups of the normal group and the abnormal group which showed articular gout and inanition.
Gout line (G-line) and non-gout line (N-line) were established from gout group and normal group respectively.
At the selected second generation, percent incidence of abnormality in gout line reached 100 percent, and that in non-gout line was 5.8 percent.
It was suggested that the gout was the autosomal single recessive character from the results of reciprocal crossing experiment with both lines.

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Blood samples were taken from about 600 fowls of 24 Japanese native breeds to study the phylogenetic relationships of these breeds. Genetic polymorphisms of albumins, esterases and alkaline phosphatases of fowl plasma were detected using horizontal starch gel electrophoresis.
Plasma albumins of the fowl are controlled by three autosomal alleles, Alb^A, Alb^B and Alb^C (STRATIL, 1968). In most of Japanese native breeds, the gene frequency of Alb^B was high. Alb^A was observed only Jitokko. Alb^C was present in Shamo (Japanese Games), and Minohiki and Satsumadori, both of which were phylogenetically related to Shamo breed, and the breeds of Tosajidori, Uzurao and Ohiki.
Plasma esterases are controlled by three autosomal codominant alleles (GRUNDER, 1971). Gene frequency of Es-1^B was higher than those of Es-1^A and Es-1^C in most of Japanese native breeds, Es-1^C being the lowest, whereas Es-1^A was predominant in Mediterranean breeds. A higher frequency of Es-1^C was observed in Ohiki and Koshamo (Japanese Game Bantam), small breeds.
Plasma alkaline phosphatase of the fowl was observed in two electophoretic regions. One is controlled by the dominant (Akp) and recessive (akp) alleles (WILCOX, 1966), and the other is controlled by the dominant (Akp-2^o) and recessive (Akp-2^a) alleles GODA et al., 1971). Gene frequency of Akp was higher in Onagadori, Totenko and Uzurao, which were charactaristic to have white ear lobes, than the other breeds. Low frequency of Akp was observed in Shokoku having red ear lobes. It is postulated that Totenko was a more possible ancestor of Onagadori (Long Tailed Japanese fowl) than Shokoku.

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Escherichia coli and Staphylococcus aureus were used to artificially contaminate egg shells for evaluation of formaldehyde fumigation. Formaldehyde was liberated from 40ml of formalin mixed with 20g of potassium permanganate per 1m³ of room capacity. Even after fumigation for 3.0 hours, surviving bacteria were detected when an egg was heavily contaminated with bacteria. No bacteria were recovered when the contaminated egg shell was washed with water before fumigation. This was thought to be due to a decrease in the number of bacteria on the egg shell surface as a result of washing.
When producing SPF chicks, dirty eggs including slightly soiled eggs, should not be used for hatching. Only for the the production of commercial chicks, slightly soiled eggs should be used for hatching after washing.

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Experimental condition for biological assay of phosphorus availability by chicks was studied. Breed difference was observed in incidence of ricket of one-day-old chicks fed low phoshorus diet containing 0.3% of phosphorus from soybean meal. Ricket could be prevented by using 7-day-old White Leghorn male chicks reared on the restricted feeding program. Ten days of experimental period was satisfactory to get similar conclusion to those obtained by bioassay of 3 or 4 weeks of period. Toe ash content was superior to tibia ash content. Linear relationship between dietary added phosphorus and toe ash content was observed within the range of added phosphorus from 0 to 0.3%.
A simplified bioassay procedure of ten days of feeding period is recommended, which is a slope ratio assay of linear regression lines between added phosphorus and toe ash content.
Availability and its 95% fiducial interval of phosphorus in feed grade dibasic calcium phosphate were 99% and 115-84%, respectively. Those of phosphorus in fish meal were 109% and 127-90%, respectively. Those of phosphorus in yellow corn were 0% and 33--31%, respectively.

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White Leghorn pullets were fed rations containing 0, 10, 15 and 20% dried poultry waste (DPW) for the period of 4-66 weeks of age. No significant difference in egg production, egg weight, mortality, fertility, and hatchability was observed among the groups received the different levels of DPW. There was a linear decrease in basal diet consumption with each percentage increase in DPW. Feed conversion ratios based on the basal diet (basal diet consumption/egg mass) of the pullets fed the diet containing 15 and 20% DPW was 8% lower that that of the birds fed the basal diet. No significant differences in the palatability were observed between the boiled eggs obtained from the pullets fed the ratios containing 0 and 20% DPW.

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