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Abnormal Appetite of Laying Hens in Feeding Experiments*
Abnormal Appetite of Laying Hens in Feeding Experiments* G. DAVIS BTJCKNER, W. M . T N S K O , J R . , AND AMANDA H. HENRY
Kentucky Agricultural Experiment Station, Lexington, Kenlttcky (Received for publication June 30,1944)
* The investigation reported in this paper is in connection with a project of the Kentucky Agricultural Experiment Station and is published by permission of the Director.
though the mother hens eat it in large quantities and have been observed to attempt to teach young chicks to eat blades of grass or leaves of succulent clover. This paper is concerned with the consumption of, or appetite for, grass and other materials by laying hens. Following an experiment with laying hens where it was found that the consumption of different feeds varied widely with individual hens, this experiment was\planned to determine the consumption of pasture bluegrass when used as a supplement to an all mash ration. Twenty-four Rhode Island Red yearling hens were confined in laying houses for six weeks on an all-mash laying ration; then, on August 21, 1943, after the late summer growth of grass had started, they were given access to a bluegrass pasture. After two weeks on the range, 12 hens selected at random were weighed, killed, and the gizzard removed. The contents of the gizzard was dried, weighed, and examined. The weight of the hens, approximate percentages of grass in the contents of the gizzard, the weight of the dry gizzard contents and the percentages of hens in each group are given in the accompanying table. Here it will be observed that the gizzards of three (25 percent) of the hens contained no grass. Contents of two of the gizzards (17 percent) was approximately 98 percent grass, while in the other seven gizzards (58 percent) the amount of grass varied from 25 to 65 percent. 120
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 22, 2015
A PPETITE or hunger may be defined •*• • primarily as sensation resulting from need for food. Appetite may be mild hunger. With the chicken it may be that hunger or appetite is in a measure associated with habit since hens after having consumed their fill of any feed are passive, but will immediately recommence eating should a new supply of the same feed be added to the partly filled trough, a frequently repeated operation. Reflected light may also play a distinct part in the urge of chickens to consume certain food, as is witnessed by the picking at a gold ring or other shiny metal brought before them. This too is shown by the fact that chickens as a rule prefer oyster shell or cystalline calcite or other shiny material to the dull nonreflecting rock limestone which serves the same purpose of supplying calcium. Experiments have shown that many chickens prefer certain types of ground seed and are particularly eager to consume hemp seed, this being among the most preferred of many seeds and grains contained in a miscellaneous mixture placed before them. This may be the result of odor. Other experiments have shown that young chicks consume very little, if any, growing grass or other succulent herbage in a pasture until after the 7th week, even
ABNORMAL APPETITE or LAYING HENS IN FEEDING EXPERIMENTS
121
Other instances of abnormal appetites of hens have been observed and could be discussed but this particular example shows definitely that in metabolism and feeding experiments with laying hens and probably with animals in general the individual appetite, hunger or need for
food of the animal under consideration must be considered. This can be done by the examination of the excreta -and the contents of the digestive system.
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 22, 2015
The photograph shows the contents of the gizzard containing approximately 98 percent grass and of one containing no distinguishable grass. The fact that some gizzards contained no grass indicates that these hens either did not crave it or had not been accustomed to eating it, while those hens whose gizzards contained 98 percent grass showed a distinct craving for this herbage, at least for a period of time, because the mash was before them at all times. The comparatively large number of hens whose gizzards contained intermediate and varying percentages of grass indicates that their appetitites were probably normal and the appetites of the others were abnormal. The latter should not be construed as hunger, as a general proposition, but more probably as the result of an obscure urge to obtain some material which apparently was lacking in the feed as far as the individual hens were concerned.
Kentucky Agricultural Experiment Station, Lexington, Kenlttcky (Received for publication June 30,1944)
* The investigation reported in this paper is in connection with a project of the Kentucky Agricultural Experiment Station and is published by permission of the Director.
though the mother hens eat it in large quantities and have been observed to attempt to teach young chicks to eat blades of grass or leaves of succulent clover. This paper is concerned with the consumption of, or appetite for, grass and other materials by laying hens. Following an experiment with laying hens where it was found that the consumption of different feeds varied widely with individual hens, this experiment was\planned to determine the consumption of pasture bluegrass when used as a supplement to an all mash ration. Twenty-four Rhode Island Red yearling hens were confined in laying houses for six weeks on an all-mash laying ration; then, on August 21, 1943, after the late summer growth of grass had started, they were given access to a bluegrass pasture. After two weeks on the range, 12 hens selected at random were weighed, killed, and the gizzard removed. The contents of the gizzard was dried, weighed, and examined. The weight of the hens, approximate percentages of grass in the contents of the gizzard, the weight of the dry gizzard contents and the percentages of hens in each group are given in the accompanying table. Here it will be observed that the gizzards of three (25 percent) of the hens contained no grass. Contents of two of the gizzards (17 percent) was approximately 98 percent grass, while in the other seven gizzards (58 percent) the amount of grass varied from 25 to 65 percent. 120
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 22, 2015
A PPETITE or hunger may be defined •*• • primarily as sensation resulting from need for food. Appetite may be mild hunger. With the chicken it may be that hunger or appetite is in a measure associated with habit since hens after having consumed their fill of any feed are passive, but will immediately recommence eating should a new supply of the same feed be added to the partly filled trough, a frequently repeated operation. Reflected light may also play a distinct part in the urge of chickens to consume certain food, as is witnessed by the picking at a gold ring or other shiny metal brought before them. This too is shown by the fact that chickens as a rule prefer oyster shell or cystalline calcite or other shiny material to the dull nonreflecting rock limestone which serves the same purpose of supplying calcium. Experiments have shown that many chickens prefer certain types of ground seed and are particularly eager to consume hemp seed, this being among the most preferred of many seeds and grains contained in a miscellaneous mixture placed before them. This may be the result of odor. Other experiments have shown that young chicks consume very little, if any, growing grass or other succulent herbage in a pasture until after the 7th week, even
ABNORMAL APPETITE or LAYING HENS IN FEEDING EXPERIMENTS
121
Other instances of abnormal appetites of hens have been observed and could be discussed but this particular example shows definitely that in metabolism and feeding experiments with laying hens and probably with animals in general the individual appetite, hunger or need for
food of the animal under consideration must be considered. This can be done by the examination of the excreta -and the contents of the digestive system.
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 22, 2015
The photograph shows the contents of the gizzard containing approximately 98 percent grass and of one containing no distinguishable grass. The fact that some gizzards contained no grass indicates that these hens either did not crave it or had not been accustomed to eating it, while those hens whose gizzards contained 98 percent grass showed a distinct craving for this herbage, at least for a period of time, because the mash was before them at all times. The comparatively large number of hens whose gizzards contained intermediate and varying percentages of grass indicates that their appetitites were probably normal and the appetites of the others were abnormal. The latter should not be construed as hunger, as a general proposition, but more probably as the result of an obscure urge to obtain some material which apparently was lacking in the feed as far as the individual hens were concerned.