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In a 4 x 2 factorial experiment, 672 White Leghorn hens were given diets with four levels (0, 10,20 and 40 g kg-I) of sunflower seeds and two levels (7.0 and 8.0 g kg-I) of dietary lysine from 43 to 67 weeks of age. The inclusion of increasing levels of sunflower seeds in the diet increased (P

A diet containing 10 per cent protein and 11.31 MJ M.E. kg-1 was fed to six groups of eggtype pullets from either day old or four weeks for 8, 12 and 16 weeks in both summer and winter. The same diet was also fed to another group from 8 to 20 weeks of age in both seasons. During the rest of the rearing period of each treatment a diet containing 16 per cent protein was fed to 20 weeks of age. The control group was fed a diet containing 20,16 and 12 per cent protein and 12.1 5 MJ M.E. kg-1 from day old, 6 and 14 weeks of age respectively. In both seasons, feeding the restrictive diet resulted in a reduction in the cost of feeding and in body weight gain to 20 weeks of age; and a delay in maturity compared with the control without adversely affecting egg production traits or increasing food consumption during the laying phase. Pullets fed the restrictive diet from day old ate less food during rearing, matured later and tended to lay smaller eggs throughout the laying period than their counterparts which were restricted from four to eight weeks of age in both experiments. Food consumption was not affected by the duration of restriction in either rearing season. However, feeding costs and body weight of pullets at the end of both rearing seasons were reduced progressively by increasing the duration of restriction. Rate of mortality was not affected by the rearing treatments when the birds were reared in summer, whereas in winter pullets restricted from day old for 12 to 16 weeks had the higher rate of mortality. Mortality during laying was not affected by the rearing treatments in either season. The results of both experiments suggest that for maximum return the optimum age for feeding the low protein diet is from 4 to 20 weeks of age in either season.

Three of five groups of White Leghorn x Australorp hens aged 73 weeks, housed in cages, were fed a laying diet containing zinc (23.7 g/kg), or iodine (4.1 g/kg), or calcium (1.0 g/kg). The fourth group of hens was given only whole-grain barley while a fifth group given a normal laying diet served as the control. All groups were fed their respective diets until rate of lay dropped to 0% or less than 2%, and they were then given a normal laying diet until 97 weeks of age. Water was available at all times and 15.5 h of constant light was provided daily to all treatments throughout the experiment. Hens given the zinc and the whole-grain barley diets ceased egg production within 1 week and remained out of production for about 10 days. The hens in both of these treatments reached peak egg production (67%, on a hen day basis) 8 weeks after the initiation of treatments, after which they continued to lay at a higher rate than those given iodine, calcium and control treatments. Hens given the diets with either iodine or calcium reached their lowest rate of lay (1.6%) after 15 and 7 days of feeding the two diets respectively. They resumed laying immediately after the resumption of feeding the normal laying diet and reached peak egg production (59%) at 8 and 12 weeks after feeding the iodine and calcium diets respectively. The treated hens laid eggs with higher Haugh units and specific gravity values than those eggs of the controls. The lowest rate of decline in both those traits, from the pre-treatment values, was in the zinc and barley treatments. These treatments also had the lowest percentage of cracked eggs. There was no significant difference among treatments in mean rate of lay, egg weight, or rate of mortality from 73 to 97 weeks of age. The present results suggest that feeding wholegrain barley can be used successfully to extend the productive life of laying hens beyond the first year of egg production if such an extension is desirable in a given economic situation. It is a simpler technique than the conventional method of induced moulting and the method of feeding a high level of zinc.

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