Report on the Agricultural Experiment Stations, 1952 Page: 78
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78 REPORT ON EXPERIMENT STATIONS, 1952
from family 6 were mated to random-bred stock to produce topcross
progeny. The egg production of the topcross progeny has been excellent.
During a test period of 120 days, these birds had an 80-percent
production as compared with a 74-percent production for the best
pen of random-bred birds.
Developing nonbroody chickens
A nonbroody line of Rhode Island Red chickens developed by the
Massachusetts station has shown complete freedom from the broody
instinct through three generations. This is strong evidence that the
line is now genetically free from genes for broodiness. Through the
use of conventional methods of line breeding and trapnesting prior to
1947, the incidence of broodiness had been reduced as low as 1 percent,
but could not be completely eliminated. Final eradication was accomplished
by injecting all females with the hormone prolactin, and
selecting as breeders pullets which exhibited little or no reaction to the
Multiplane turning increases hatch
Early work at the Iowa station (1930) and the Department indicated
that multiplane turning of eggs will increase the hatch. Present
research at the Missouri station verifies these early findings. Turning
eggs in an incubator in six different positions or on several planes,
rather than in the two conventional positions used in nearly all of
the modern incubators, will eliminate much of the loss from dead
embryos during the later stages of incubation, according to the Missouri
station. Multiplane turning reduced the percentage of embryos
developing with head-between-thighs, feet-over-head, and beak away
from the air cell. There was a relative decrease of 73 percent in the
embryos with head-between-thighs. A 3-percent better hatch occurred
among multiplane-turned eggs than among eggs turned only
in the conventional way under identical conditions in the same incubator.
The chicks from the former eggs hatched several hours earlier
than those from the latter, were "fluffed out" sooner, and in general
appeared to be in better condition.
Pretest hens for poor fertility
The New York (Cornell) station discovered that hens whose eggs
show a low fertility usually are able to maintain live spermatozoa in
their reproductive tract for a comparatively short period, only 1 day
or less. Hens with high fertility can maintain spermatozoa under
the same conditions for 14 days or more. By pretesting the females
it is possible to eliminate those in which duration of fertility is low.
A peculiar aspect of this problem is that males of the infertile strain
show unusually precocious sexual maturity, and have large combs
that lop over when the animals are as'young as 8 weeks. Coincident
with this condition the animals show excessive development of the
testes. These abnormalities are apparently associated with excessive
activity of the anterior lobe of the pituitary in immature birds.
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United States. Office of Experiment Stations. Report on the Agricultural Experiment Stations, 1952, book, January 1953; Washington D.C.. (digital.library.unt.edu/ark:/67531/metadc5990/m1/80/: accessed November 18, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.