Hyre, H. M.

Johnson, J. R.

McClung, M. R.

English

The Research Repository @ WVU (West Virginia University)

West Virginia Agricultural and Forestry ExperimentStation BulletinsDavis College of Agriculture, Natural ResourcesAnd Design1-1-1967Influence of density on production traits of layinghensH. M. HyreJ. R. JohnsonM. R. McClungFollow this and additional works at: https://researchrepository.wvu.edu/wv_agricultural_and_forestry_experiment_station_bulletinsThis Bulletin is brought to you for free and open access by the Davis College of Agriculture, Natural Resources And Design at The Research Repository@ WVU. It has been accepted for inclusion in West Virginia Agricultural and Forestry Experiment Station Bulletins by an authorized administrator ofThe Research Repository @ WVU. For more information, please contact ian.harmon@mail.wvu.edu.Digital Commons CitationHyre, H. M.; Johnson, J. R.; and McClung, M. R., "Influence of density on production traits of laying hens" (1967). West VirginiaAgricultural and Forestry Experiment Station Bulletins. 547.https://researchrepository.wvu.edu/wv_agricultural_and_forestry_experiment_station_bulletins/501I^srw/?G/iv/4iInfluence of Density onProduction Traits ofLaying HensBulletin 547 June 1967West Virginia UniversityAgricultural Experiment StationThe AuthorsH. M. Hyre is Associate Poultry Geneticist; J. R. John-son, at the time of this study, was Poultryman; and M. R.McClung is Animal Scientist.West Virginia UniversityAgricultural Experiment StationCollege of Agriculture and ForestryA. H. VanLandingham, DirectorMorgantownContentsIntroduction 5Experimental Procedures 5Results and Discussion 6Economic Aspects of the Study 13Summary and Conclusions 15Digitized by the Internet Archivein 2010 with funding fromLyrasis IVIembers and Sloan Foundationhttp://www.archive.org/details/influenceofdensi547hyreInfluence of Density onProduction Traits ofLaying HensH. M. Hyre, J. R. Johnson, and M. R. McClungIn recent years poultrymen have been allowing less space forlaying hens than once was the custom. It is now evident thathens can perform satisfactorily under what seems to be crowdedconditions. Floor management will be considered only in this in-vestigation. It is well recognized that with a management systemof less than 2 sq. ft. of floor space per bird at least two-thirds ofthe floor space should be covered with slats or wire. The hensmust be debeaked and the house should be fan-ventilated. Thenumber of birds to a given floor space is referred to as hen dens-ity. Increased density will reduce housing costs, which could re-sult in greater profits. An attempt was made here to investigatethe results from hens that were subjected to various floor densi-ties.EXPERIMENTAL PROCEDURESA mechanically ventilated building, 29' x 63', which was wellinsulated, provided the housing space for this study. The buildingwas divided into four equal pens, making available 456 sq. ft. offloor space in each pen. Three-fourths of the floor space in eachpen was covered with wire and slats, and the remainder wascovered with litter. The number of birds housed per pen was 608,456, 365, and 304, allowing %, 1, IV4. and 1^/2 sq. ft. of floor spaceper bird, respectively. All feeders and water troughs were placedon the slats and wire. The number of feeders, water troughs, andnests were identical per bird for each of the pens. All birds re-ceived 14 hours of light daily.In addition to these four pens, six other pens were used with-out wires and slats. The hen density was not as great here be-cause the feeders and waterers were placed on the floor, whichwas covered with litter, and the building was not fan-ventilated.Each pen had 200 sq. ft. of floor space and three of them had 133,100, and 80 birds each, allowing IVa, 2, and 21/2 sq. ft. of floorspace per bird. These three pens were replicated. This phase ofthe project will be discussed later.White Leghorn strain cross chicks were hatched on August4 and placed in the laying quarters on December 22, when thepullets were 140 days old. All records were started on January 1,when the birds were 150 days old. Egg production records wererecorded daily and mortality was recorded on the days that birdsdied. All eggs from each pen were weighed bi-monthly and wereclassified as extra large, large, medium, small, or peewees. In-terior egg quality and shell quality were measured monthly bydetermining the Haugh units and specific gravity of the eggsthrough random sample of eggs consisting of 15 per cent of thenumber of birds housed per pen. Body weights were recorded at140, 250, 365, and 500 days of age. The study terminated whenthe birds were 500 days of age.RESULTS AND DISCUSSIONTable 1 shows the per cent of egg production and it may benoted that the hens in pen 1 (least amount of floor space perbird) had an annual egg production of only two percentagepoints less than the hens in pen 4 (twice as much floor space).The lowest egg production was in pen 2 (1 sq. ft. of floor spaceper bird). The production in pen 3, which provided IV4 sq. ft. offloor space per bird, was essentially the same as that in pen 4with 14 sq. ft. floor space more per bird. The number of eggs pro-duced per bird to 500 days of age in pens 1, 2, 3, and 4 was 239,TABLE 1Per Cent Egg Production—Hen Housed BasisFloor Space/Bird % sq. ft. 1 sq. ft. I1/4 sq.ft. IVs sq.ft.Month i 2 3 4Pen No.January 29.92 31.49 32.04 32.77February 88.23 89.13 91.59 90.24March 83.89 85.14 86.65 87.30April 81.37 81.03 85.47 83.58May 79.73 76.89 79.19 81.31June 75.57 71.41 77.83 77.16July 72.52 61.13 74.07 75.18August 70.58 66.05 71.51 72.39September 65.27 61.88 65.89 66.12October 55.48 55.69 56.80 59.08November 55.60 51.92 57.07 58.60December 53.39 50.64 55.49 56.66X 68.01 66.27 69.81 70.38233, 245, and 247, respectively. The difference in egg productionbetween the high and low pens was only 14 eggs, even though thehigh pen provided 50 per cent more space per bird.Since the differences in egg production of the four pens weresmall and production was not in sequence with the space al-lotted, it would seem logical to assume that the difference in floorspace allowed in this study did not influence egg production.Table 2 gives the per cent mortality for the laying year. Noneof these mortality percentages would be considered excessive andthe differences between pens are not significant. Since these dif-ferences were small and they did not follow in order with thefloor space allotted, it would seem unlikely that mortality was in-fluenced by this treatment.Tables 3 and 4 present information relative to egg weight,and these data were collected and recorded in two different ways.The information in Table 3 was gathered at two-week intervalsby separating into weight grades all the eggs that were producedfor one day. Table 4 shows the average weight in grams per eggfor the various pens. To get this data random samples of eggsconsisting of 15 per cent of the number of birds housed per penwere used. While the data in these two tables show some varia-tions in egg weights between pens, it does not appear likely thatthese differences are due to floor space per bird.The shell strength of the eggs was determined by the specificgravity method using a series of salt solutions. Specific gravity ofTABLE 2Per Cent MortalitySq. Ft. of Floor Space/BirdMonth % 1 11/4 11/2January 66 .00 .00 .00February .99 .66.66.00.27.66March 1.34 .33April .51 3.11 .55 .00May .86 .69 1.38 1.99June .34 .00 .28 .34July .52 .46 .14 .68August .52 1.16 .28 .34September .87 .94 .29 1.37October .53 .95 .00 1.07November .35 .72 .00 .70December .00 .24 .00 .35Total for Year 7.07 9.21 4.38 7.57the solutions ranged from 1.062 to 1.098 with intervals of .004 be-tween salt solutions. Specific gravity scores ranged from 1 to 10with 1 equaling 1.062 specific gravity. The specific gravity scoreindicates shell thickness or shell strength, and the higher thescore the greater the shell strength. An egg with a score of 5 orbetter would have satisfactory shell strength.Table 5 shows the specific gravity of the eggs for the fourpens. These data were obtained from a random sample of eggstaken from each pen monthly. It may be noted that there is veryTABLE 3Per Cent of Large and Extra Large Eggs ProducedSq. Ft. of Floor Space/BirdMonth % 1 11/4 11/2January 2.73 2.78 1.15 1.32February 16.82 20.15 17.25 20.25March 35.79 40.18 35.91 42.77April 56.15 56.62 57.77 58.33May 66.85 70.76 68.06 74.15June 70.32 75.95 75.91 73.52July 74.97 79.52 79.00 79.21August 78.48 79.86 81.26 82.13September 83.83 87.06 81.03 84.00October 85.71 87.81 86.11 92.75November 93.44 95.76 96.77 94.86Average 62.52 64.66 63.47 66.10TABLE 4Egg Weights—GramsSq. Ft. of Floor Space/BirdMonth % 1 11/4 11/2January 43.20February 53.98March 55.57April 56.43May 58.34June 59.56August 59.70September 59.70October 62.90December 64.00X 57.3444.60 44.50 44.2054.06 54.66 55.2055.26 55.96 55.4157.44 57.21 57.5659.62 58.14 59.3359.98 58.84 59.6560.60 63.10 60.8061.20 58.10 58.8062.20 62.80 62.9063.10 63.50 65.9057.80 57.68 57.98TABLE 5Specific Gravity Score of EggsSq. Ft. of Floor Space/BirdMonth ^4 i 1% IVaJanuary 8^21 8^59 8A1 8^February 7.20 7.06 7.43 7.43March 6.46 7.19 7.91 7.15April 6.87 6.68 6.36 6.72May 6.46 6.19 5.93 5.82June 5.50 5.50 5.90 5.60August 4.40 4.30 4.30 4.70September 4.70 4.60 5.80 6.10October 5.20 4.90 5.60 4.80December 4.90 4.80 5.20 4.90X 5.99 5.98 6.28 6.17little difference in the average yearly specific gravity betweenpens, and it would appear that space per bird had little or noeffect on this trait.The Haugh units of the egg produced by the birds in thevarious pens are recorded in Table 6. Haugh Unit is a term usedto express the albumen quality of eggs and is determined fromthe height of the albumen and the weight of the eggs. U. S. gradeA eggs must have from 60 to 72 Haugh units and grade AA eggsmust have 72 Haugh units or more. The information given inTable 6 was computed from random samples of eggs taken fromTABLE 6Haugh UnitsSq. Ft. of Floor Space/BirdMonth ~^4 i U4 1%'January 93.3 92^2 93^2 97.1February 89.2 94.2 92.6 91.8March 87.2 88.9 81.3 85.4April 82.2 83.9 81.9 84.8May 77.3 79.0 77.8 79.0June 74.4 73.7 79.2 82.3August 81.1 81.6 72.1 74.0September 75.6 72.6 71.0 69.6October 72.5 75.0 72.1 74.2December 70.8 73.2 71.2 74.9X 80.36 81.43 79.24 81.319the various pens, and these data would indicate that the hendensities studied here did not influence the interior quality of theeggs produced.Table 7 gives the days of age of the pullets to the first eggproduced, 50 per cent production, and peak production for thevarious pens. These traits apparently were not influenced by hendensity,The other part of the study which involved six pens, threepens replicated, revealed similar results relative to hen density asthe four pens already discussed. This phase of the investigationstarted on January 1 and was terminated on August 16, when thebirds were 378 days old. These birds were from the same strainand same hatch as those in the other phase of the study.Table 8 shows the per cent egg production for the variousmonths and the average for the laying period by pens after thereplicates have been combined. The variation here is only onepercentage point between pens. It will be noted that the averageTABLE 7Days of Age toFloor Space/Bird 50 Per CentSq. Ft. First Egg Production Peak Production% 154 1731 153 17211/4 153 17211/2 155 171TABLE 8Per Cent Egg Production—Hen Housed BasisCombined ReplicatesSq. Ft. of Floor Space/BirdMonth ~iy2 2 2^January 34February 89March 87April 85May 81June 78July 71August 63X 74 74 7510Days Per Cent203 91.94197 93.20193 98.90193 94.7435 3488 9088 8985 8682 8276 8072 7266 64per cent production is high, but it must be remembered that thelaying period reported here includes only the first 7 Vi months. Ithas been concluded from these data that hen density in this in-vestigation did not influence egg production.Feed efficiency for the combined replicates for the variousfloor space allotted is given in Table 9. These differences are notlarge and do not occur in accordance with the floor space pro-vided per bird. Therefore, it would seem doubtful that they weredue to this treatment. Feed efficiency refers to the pounds of feedrequired to produce a dozen eggs.Table 10 shows hen mortality and it is important that thetreatment did not influence this trait.TABLE 9Feed Efficiency of Combined ReplicatesSq. Ft. of Floor Space/BirdMonth~\yz 2 %yzJanuary 4.90February 4.90March 3.32April 3.72May 3.92June 3.95July 3.82August 4.265.34 4.805.34 4.803.73 3.533.36 3.673.85 3.664.26 3.903.94 3.663.70 3.72X 3.99 4.03 3.86Per CentTABLE 10Mortality of Combined ReplicatesSq. Ft. of Floor Space/BirdMonth IVs 2 2 1/2January 0.00February 0.00March 38April 0.00May 1.12June 0.00July 76August .380.00 .621.00 0.00.51 .640.00 .64.50 .630.00 0.001.02 1.260.00 0.00Per Cent forLaying Period 2.63 3.00 3.7511The per cent of eggs that were large and extra large is givenin Table 11. There are some differences between various floorspace allotted. However, it does not appear that these differencesare caused by the hen density, since the variations in egg weightdo not show any relationship to floor space.Table 12 gives the egg weight in grams. These data do notindicate that there are any differences for this trait betweenpens.The data given in Table 13 do not show that the treatmenthad any effect on shell strength as the specific gravity of the eggsis similar for all pens. A similar condition exists for interior eggTABLE 11Per Cent of Large and Extra Large Eggs ProducedPen ReplicatesSq. Ft. of Floor Space/BirdMonth 11/2January 3.5February 18.4March 39.3April 54.7May 63.9June 71.6July 72.1August 76.8X 51.921/^2.9 7.415.7 16.044.1 37.161.6 50.065.0 62.876.3 70.179.5 68.578.0 74.554.6 49.2TABLE 12Egg Weights—GramsCombined ReplicatesSq. Ft. of Floor Space/BirdMonthJanuaryFebruaryMarchAprilMayJuneAugustX 56.2IVz 2 2% X of AU Pens46.1 48.0 45.4 46.553.2 52.8 53.9 53.256.3 55.6 54.8 55.257.3 57.4 56.4 57.159.2 59.2 57.2 58.758.9 60.4 58.1 52.260.7 60.8 59.9 60.556.4 55.2 56.012TABLE 13Specific Gravity Score of Eggs of Combined ReplicatesSq. Ft. of Floor Space/BirdMonth 'TVz 2 2^January 9.34February 7.04March 6.91April 6.42May 6.59June 6.39August 5.458.86 9.126.92 7.166.98 6.846.50 6.846.35 6.225.65 5.755.30 5.50X 6.8 6.6 6.8Haugh Units forTABLEEgg Quality14for Combined Replicates)nthSq Ft. of Floor Space/BirdM( 11/2 2 21/2January 94.2February 86.8March 87.6April 86.0May 78.9June 75.4August 77.296.0 95.285.5 84.785.8 86.487.9 85.680.3 80.376.6 79.477.9 78.5X 83.7 84.2 84.3quality as may be noted in Table 14. Here the variations inHaugh units between pens do not show any material differences.Days of age to first egg, to 50 per cent production, and topeak production are all shown in Table 15. These data show thathen density failed to influence the time that these periods of pro-duction occurred.ECONOMIC ASPECTS OF THE STUDYData collected in this investigation failed to reveal any influ-ence from hen density on egg production traits, such as egg num-ber, egg size, hen mortality, interior egg quality, and shell qual-ity. There is a difference, however, in the number of eggs pro-duced in each pen, and this would influence the housing costs perdozen of eggs produced. An increased number of eggs from agiven space would reduce housing costs per dozen.13TABLE 15Days of Age toFloor Space/BirdSq. Ft. First Egg50 Per CentProduction Peak Production11/2221/2150150151172171171Days202201195Per Cent949495Information from pens 1, 2, 3, and 4 revealed that as spaceper bird increased the number of eggs per hen increased onlyslightly. Table 17 shows the number of eggs produced per bird aswell as the number produced in each pen. It may be noted thatpen 1 had 100 per cent more hens than pen 4 and produced 94per cent more eggs. Even though some more equipment is re-quired as hen numbers increase, the housing and equipment costsper dozen of eggs decrease as number of eggs per pen increase.An estimate from the results of this work indicates that housingand equipment costs per dozen of eggs produced was .7 of a centin pen 1 and .9 of a cent in pen 4. Assuming that returns aboveall costs in pen 4 were 5 cents per dozen then the returns aboveall costs in pen 1 would logically be 5.2 cents per dozen. If theseconditions can be accepted, then the returns above costs fromTABLE 16Number of Dozen Eggs ProducedFloor Space/BirdSq. Ft. Dozensiy2221/23,7263,1422,280dozendozendozenTABLE 17Egg Production Per PenFloor Space/BirdSq. Ft. Hens/Pen Eggs/HenNo.Eggs/PenDoz.Eggs/Pen3/4 608 2391 456 2331 1/4 365 24511/2 304 247145,312106,24889,42575,08812,1098,8547,4526,25714pen 1 would be $.052 x 12,109 or $629.67 while the returns frompen 4 would be $.05 x 6,257 or $312.85.SUMMARY AND CONCLUSIONSHen density was studied on slat floors and litter floors. Dataregarding egg production, egg size, mortality, feed conversion,interior egg quality and shell quality were collected. Hens on theslatted floors were allotted %, 1, l^A, and IVz sq. ft. of floor spaceper bird. Hens on the litter floors were given 11/2, 2 and 2 V2 sq. ft.of floor space per bird. There were some slight differences in theegg production traits between pens, but they were not consideredgreat enough to be of economic importance. The data collectedin this study indicate that it would be more profitable to houseproduction hens at high density.15

Influence of density on production traits of laying hens

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Influence of density on production traits of laying hens

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