ABSTRACT
Techniques are described for removing and replacing approximately 15% of the total volume of yolk after 5 days’ incubation, or of albumen after 2-3 days’, in hens’ eggs. These allow up to 50 and 40% respectively of the eggs to hatch.
Yolk and albumen were exchanged between different breeds of chickens, and chicken eggs received yolk and albumen from other species. Embryonic viability was not reduced by egg constituents of other breeds or species. Small numbers of chickens from eggs which received turkey, goose and duck yolk, and larger numbers from eggs which received turkey albumen, were hatched and reared successfully; they appeared to be quite normal.
Legbar eggs received yolk from Polish Bantam eggs. The experimental birds weighed significantly less than their control siblings at 139 days. The mean shank lengths were not significantly different. Attempts to repeat the experiment failed to support this result ; possible reasons for this are discussed.
Polish Bantam eggs received yolk from Dorbar eggs. At 100 days they were significantly heavier than their control siblings, but their mean shank lengths were almost identical.
In each of the four 1955 albumen exchange experiments the mean weight of the experimental birds at 170 days was greater than that of their control siblings, but not significantly so. On pooling the data a significant difference was found at 100 and 114 days (P=0-05) and 170 days (P<0·02). The mean shank lengths were very similar. The 1956 experiments failed to confirm these results; possible reasons for this are discussed.
It appears that, in certain circumstances, exposure of the embryo to ‘foreign’ yolk or albumen may influence post-hatching growth in weight, but this effect is only detectable when the chicks are over 3 months old.
This agrees with Hašek’s (1952a) observations on ducks which received chicken egg albumen.
