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Wet Litter in the Poultry House1
'^.
WET LITTER IN THE POULTRY HOUSE ^ A. B. DANN Manager Poultry Division Jamesway Farm Engineers
1 A paper prepared for the Annual Convention of the American Association of Instructors and Investigators in Poultry Husbandry, Ottawa, Canada, August 21 to 24, 1923.
15
7
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 12, 2015
Wet litter in the poultry house is a rather troublesome problem to most poultrymen. It is not a fit place in which to feed the scratch grain, is quite generally conceded to be a favorable medium for the development of colds, catarrh, roup, and like maladies and, therefore, necessitates extra labor and excessive litter material, due to the necessity of frequent changing. Because of these difficulties, it is only logical that one of the first considerations of good housing of hens involves a study of the cause and possible means of control of wet litter. Briefly, the causes may be listed as follows : 1. Water coming up through the floor by capillary action from the ground below. 2. Rain water coming in through open windows or leaky roofs. 3. Water as spillage from inadequate and unsanitary drinking vessels. 4. Water from droppings of birds. 5. Water from condensation of moisture in the expelled breath of the hens and, under certain conditions, from the air brought into the poultry house through open windows, bafflers, and the like. 6. Drip from wall, windows, and ceiling where moisture has condensed from the air of the poultry house, due to inadequate construction and ventilation. The first three conditions seem easy of correction by means of suitable floor and roof construction, proper window arrangement and adequate poultry waterers properly managed. It is surprising, however, how frequently one will find these simple factors overlooked even on so-called modern poultry farms. It seems fitting, therefore, to consider these factors briefly. Before doing so, however, let me suggest the importance of the floor in the poultry house. In the dairy barn, we> separate
16
POULTRY
SCIENCE
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 12, 2015
the floor into certain units, each designed for a specific purpose. There is the feeding alley with the manger divisions setting off a portion from which the cow eats. Then a portion is set aside for the cow's personal comfort and usually fitted with cork brick on which she can stand or lie with ease. Next comes the gutter fot the collection of the excreta for removal two or three times each day. Finally there is the portion allotted to the caretaker as a walk or passageway behind the cows. How different all this is in the poultry house. All the parts of the floor must serve a quadruple purpose, viz : passageway for the caretaker, a feeding place for the hens, a comfortable place on which they stand or move about, and finally a suitable medium for the collection of droppings. This magnifies the importance of a good floor with suitable litter material of the proper depth. It is stated on good authority that moisture may be raised by capillary action some seven or eight feet through sand or gravelly soil, and twice or three times this distance through the heavier soils. The use of roofing material between the floor surface and the ground is, therefore, essential in practically every poultry house where the floor comes in contact with the ground underneath. Boofs must be kept in repair and open windows protected from inbeating rain. Waterers must be kept leak-proof and arranged so that the hen stands in a comfortable position to drink. If she must reach too far she will withdraw her head and the drip from her beak and wattles goes on the litter below. The caretaker should avoid spillage in filling, emptying or cleaning waterers. These things are important as pointed out later. Wet litter caused by free water in the droppings of the birds and by condensation of moisture from the breath of the hens and from the air above the litter presents a far more difficult problem and has been made the subject of considerable study by the research department of the company with which I am associated. It is a pleasure for me to present a little of the data from our research work in the field of poultry housing, and it may interest you to know that a paper bearing on this subject was presented at the annual convention of the American Society of Heating and Ventilating Engineers at their last annual convention in Washington, D. C.
WBT
LITTER
IN THE POULTRY
HOUSE
17
Input
Assimilation ALL
12.734 8.788 0.955 29.800 213.238
lbs. lbs. lbs. lbs. lbs.
grain mash g r i t & shell water air
Output
MATERIALS
0.039 lbs. gain in weight
5.645 lbs. eggs 37.108 lbs. excreta 222.723 lbs. air, w a t e r vapor and methane 265.476 lbs. Total
265.515 lbs. Total W A T E B ONLY
2.172 lbs. in feed 1.723 lbs. inhaled 29.800 lbs. in d r i n k 33. 695 lbs. Total
0.0218 lbs. gain in weight
3.723 lbs. in eggs 8.652 lbs. exhaled 21.298 lbs. in excreta 33.673 lbs. Total
R E S U M E P E R 24-HOUR DAY P E R 100 LEGHORNS W E I G H I N G 373 POUNDS Total Weight Excreta 37.108 lbs. -jLt-.r-i'^W a t e r in excreta when dropped 21.298 lbs. çrry^^Ji^.'-^-^^ W a t e r retained in a i r dry e x c r e t a - 2.530 lbs. "^ "^ W a t e r to be evaporated from excreta 18.768 lbs. J^^ '^'''^ W a t e r spilled into litter by d r i n k i n g 0.927 lbs. >j W a t e r to be evaporated from litter 19.695 lbs. W a t e r given off t h r o u g h respiration system 8.652 lbs. W a t e r to be removed from poultry house 28.347 lbs.
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 12, 2015
Any scientific attempt to control the condition of litter in the poultry house must presuppose a knowledge of the moisture problem with which one is dealing. This involves a study of the moisture taken into the poultry house by all agencies and the means by which it may be removed from the house. Two conditions were considered, viz., the conditions that are reported in data already available and secondly the conditions as they existed during severe winter weather in a southern Wisconsin poultry house twenty feet wide and fifty-two feet long, housing 396 Leghorns, of which number about one-half were hens and one-half pullets. " The flock was laying at the rate of about 45 per cent. The following tables indicate the input, the assimilation and the output of moisture, based on 100 Leghorns weighing 373 pounds, and for a period of one 24-hour day.
18
POULTRY
SCIENCE
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 12, 2015
When hens are on roosts ten hours per day and on the floor fourteen hours per day, the water to be evaporated from floor litter is 11.875 pounds. Water to be evaporated from droppings board is 7.820 pounds. This represents a very definite statement of the problem that confronts us if we are to have dry litter in the poultry house. It is to be remembered, too, that the above figures include only the free water in droppings and apply only to poultry houses so constructed that no moisture comes into the litter by capillary action from the ground below or from leakage or condensation from the air above. Our problem is a big one and deserves careful study. The rate of evaporation will depend on available heat, on rate of air movement over litter, on depth of litter and on frequency of turnover of litter. While it is not within the scope of this paper to discuss complete control, it seems only fitting that a iew factors should be presented for consideration. The heat produced by hens and made available for heating the house is rather limited in amount. But when properly used, there is sufficient heat available to solve the moisture problem. To illustrate: with Leghorn hens we have found the available heat per 3%-pound hen to approximate 42 B. T. U. per hour. Given 2.5 square feet of floor area per bird in a poultry house averaging six and one-half feet in height and with a heat loss through walls, ceiling, floor and windows that does not exceed .22 B. T. U. per square foot per hour per degree difference in temperature inside and outside, a temperature can be maintained in the poultry house that is fifteen to thirty degrees higher than the out-of-doors temperature. This is sufficient to evaporate the moisture, and will maintain a satisfactory condition of the litter. As to rate of air movement over litter we have found the optimum to be about five to six feet per minute, which creates no perceptible draft and yet changes the air sufficiently often to keep it pure and to move off the moisture-laden atmosphere. While on this' subject and in consideration of the rather widely discussed question of ventilation, let me pause to say that change of air alone will not necessarily keep a poultry house dry. It is but one factor and has to do with moving the moisture out of
WET LITTER
IN THE POULTRY HOUSE
19
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 12, 2015
the building once it is evaporated and is in the form of moisture or "cold steam" in the atmosphere. The depth of litter has a striking effect on the rate of evaporation. We have found that litter over four inches deep is not to be desired. I t acts as a cushion of entrained air pockets which become saturated with moisture and through which evaporation proceeds slowly or not at all. The frequency of turnover of litter also has a marked effect on evaporation. It breaks up the saturated air pockets above referred to and exposes the different wet surfaces of the litter to the air above it. This also coincides with good feeding practice in cold or damp weather which makes it advisable to feed a little grain at frequent intervals during the day. To summarize in one general statement the conditions of evaporation of moisture from litter : ' ' Litter is a very porous material holding much entrained air. Whenever the temperature of the litter is higher than the air above it the entrained air, due to its temperature, will hold a large number of vapor particles and bring its vapor pressure in equilibrium with that of the remaining moisture in the litter and therefore retard evaporation from deep litter when left in a quiet state. Thus the heat required to maintain the process should be supplied from the air above the litter." This involves four things : (1) An insulated and water-proofed floor which is not appreciably affected by temperature or moisture from below. (2) Ceiling, wall, and window construction that will not permit of excessive heat loss. (3) A sufficient number of birds to provide animal heat or, lacking this, the necessary artificial heat to maintain as high an inside temperature as is consistent with good health and economy. (4) An adequate and controllable ventilation system for turnover of air. Are we giving ourselves a handicap when we continue to build poultry houses open to the elements and subject to the caprice of the weather? Are we fairly conducting feeding and breeding tests in poultry houses wherein we have no control over temperature, moisture and a i r ^ t h r e e most vital factors in determining the efficiency of human and animal endeavor?
WET LITTER IN THE POULTRY HOUSE ^ A. B. DANN Manager Poultry Division Jamesway Farm Engineers
1 A paper prepared for the Annual Convention of the American Association of Instructors and Investigators in Poultry Husbandry, Ottawa, Canada, August 21 to 24, 1923.
15
7
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 12, 2015
Wet litter in the poultry house is a rather troublesome problem to most poultrymen. It is not a fit place in which to feed the scratch grain, is quite generally conceded to be a favorable medium for the development of colds, catarrh, roup, and like maladies and, therefore, necessitates extra labor and excessive litter material, due to the necessity of frequent changing. Because of these difficulties, it is only logical that one of the first considerations of good housing of hens involves a study of the cause and possible means of control of wet litter. Briefly, the causes may be listed as follows : 1. Water coming up through the floor by capillary action from the ground below. 2. Rain water coming in through open windows or leaky roofs. 3. Water as spillage from inadequate and unsanitary drinking vessels. 4. Water from droppings of birds. 5. Water from condensation of moisture in the expelled breath of the hens and, under certain conditions, from the air brought into the poultry house through open windows, bafflers, and the like. 6. Drip from wall, windows, and ceiling where moisture has condensed from the air of the poultry house, due to inadequate construction and ventilation. The first three conditions seem easy of correction by means of suitable floor and roof construction, proper window arrangement and adequate poultry waterers properly managed. It is surprising, however, how frequently one will find these simple factors overlooked even on so-called modern poultry farms. It seems fitting, therefore, to consider these factors briefly. Before doing so, however, let me suggest the importance of the floor in the poultry house. In the dairy barn, we> separate
16
POULTRY
SCIENCE
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 12, 2015
the floor into certain units, each designed for a specific purpose. There is the feeding alley with the manger divisions setting off a portion from which the cow eats. Then a portion is set aside for the cow's personal comfort and usually fitted with cork brick on which she can stand or lie with ease. Next comes the gutter fot the collection of the excreta for removal two or three times each day. Finally there is the portion allotted to the caretaker as a walk or passageway behind the cows. How different all this is in the poultry house. All the parts of the floor must serve a quadruple purpose, viz : passageway for the caretaker, a feeding place for the hens, a comfortable place on which they stand or move about, and finally a suitable medium for the collection of droppings. This magnifies the importance of a good floor with suitable litter material of the proper depth. It is stated on good authority that moisture may be raised by capillary action some seven or eight feet through sand or gravelly soil, and twice or three times this distance through the heavier soils. The use of roofing material between the floor surface and the ground is, therefore, essential in practically every poultry house where the floor comes in contact with the ground underneath. Boofs must be kept in repair and open windows protected from inbeating rain. Waterers must be kept leak-proof and arranged so that the hen stands in a comfortable position to drink. If she must reach too far she will withdraw her head and the drip from her beak and wattles goes on the litter below. The caretaker should avoid spillage in filling, emptying or cleaning waterers. These things are important as pointed out later. Wet litter caused by free water in the droppings of the birds and by condensation of moisture from the breath of the hens and from the air above the litter presents a far more difficult problem and has been made the subject of considerable study by the research department of the company with which I am associated. It is a pleasure for me to present a little of the data from our research work in the field of poultry housing, and it may interest you to know that a paper bearing on this subject was presented at the annual convention of the American Society of Heating and Ventilating Engineers at their last annual convention in Washington, D. C.
WBT
LITTER
IN THE POULTRY
HOUSE
17
Input
Assimilation ALL
12.734 8.788 0.955 29.800 213.238
lbs. lbs. lbs. lbs. lbs.
grain mash g r i t & shell water air
Output
MATERIALS
0.039 lbs. gain in weight
5.645 lbs. eggs 37.108 lbs. excreta 222.723 lbs. air, w a t e r vapor and methane 265.476 lbs. Total
265.515 lbs. Total W A T E B ONLY
2.172 lbs. in feed 1.723 lbs. inhaled 29.800 lbs. in d r i n k 33. 695 lbs. Total
0.0218 lbs. gain in weight
3.723 lbs. in eggs 8.652 lbs. exhaled 21.298 lbs. in excreta 33.673 lbs. Total
R E S U M E P E R 24-HOUR DAY P E R 100 LEGHORNS W E I G H I N G 373 POUNDS Total Weight Excreta 37.108 lbs. -jLt-.r-i'^W a t e r in excreta when dropped 21.298 lbs. çrry^^Ji^.'-^-^^ W a t e r retained in a i r dry e x c r e t a - 2.530 lbs. "^ "^ W a t e r to be evaporated from excreta 18.768 lbs. J^^ '^'''^ W a t e r spilled into litter by d r i n k i n g 0.927 lbs. >j W a t e r to be evaporated from litter 19.695 lbs. W a t e r given off t h r o u g h respiration system 8.652 lbs. W a t e r to be removed from poultry house 28.347 lbs.
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 12, 2015
Any scientific attempt to control the condition of litter in the poultry house must presuppose a knowledge of the moisture problem with which one is dealing. This involves a study of the moisture taken into the poultry house by all agencies and the means by which it may be removed from the house. Two conditions were considered, viz., the conditions that are reported in data already available and secondly the conditions as they existed during severe winter weather in a southern Wisconsin poultry house twenty feet wide and fifty-two feet long, housing 396 Leghorns, of which number about one-half were hens and one-half pullets. " The flock was laying at the rate of about 45 per cent. The following tables indicate the input, the assimilation and the output of moisture, based on 100 Leghorns weighing 373 pounds, and for a period of one 24-hour day.
18
POULTRY
SCIENCE
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 12, 2015
When hens are on roosts ten hours per day and on the floor fourteen hours per day, the water to be evaporated from floor litter is 11.875 pounds. Water to be evaporated from droppings board is 7.820 pounds. This represents a very definite statement of the problem that confronts us if we are to have dry litter in the poultry house. It is to be remembered, too, that the above figures include only the free water in droppings and apply only to poultry houses so constructed that no moisture comes into the litter by capillary action from the ground below or from leakage or condensation from the air above. Our problem is a big one and deserves careful study. The rate of evaporation will depend on available heat, on rate of air movement over litter, on depth of litter and on frequency of turnover of litter. While it is not within the scope of this paper to discuss complete control, it seems only fitting that a iew factors should be presented for consideration. The heat produced by hens and made available for heating the house is rather limited in amount. But when properly used, there is sufficient heat available to solve the moisture problem. To illustrate: with Leghorn hens we have found the available heat per 3%-pound hen to approximate 42 B. T. U. per hour. Given 2.5 square feet of floor area per bird in a poultry house averaging six and one-half feet in height and with a heat loss through walls, ceiling, floor and windows that does not exceed .22 B. T. U. per square foot per hour per degree difference in temperature inside and outside, a temperature can be maintained in the poultry house that is fifteen to thirty degrees higher than the out-of-doors temperature. This is sufficient to evaporate the moisture, and will maintain a satisfactory condition of the litter. As to rate of air movement over litter we have found the optimum to be about five to six feet per minute, which creates no perceptible draft and yet changes the air sufficiently often to keep it pure and to move off the moisture-laden atmosphere. While on this' subject and in consideration of the rather widely discussed question of ventilation, let me pause to say that change of air alone will not necessarily keep a poultry house dry. It is but one factor and has to do with moving the moisture out of
WET LITTER
IN THE POULTRY HOUSE
19
Downloaded from http://ps.oxfordjournals.org/ at Florida International University on June 12, 2015
the building once it is evaporated and is in the form of moisture or "cold steam" in the atmosphere. The depth of litter has a striking effect on the rate of evaporation. We have found that litter over four inches deep is not to be desired. I t acts as a cushion of entrained air pockets which become saturated with moisture and through which evaporation proceeds slowly or not at all. The frequency of turnover of litter also has a marked effect on evaporation. It breaks up the saturated air pockets above referred to and exposes the different wet surfaces of the litter to the air above it. This also coincides with good feeding practice in cold or damp weather which makes it advisable to feed a little grain at frequent intervals during the day. To summarize in one general statement the conditions of evaporation of moisture from litter : ' ' Litter is a very porous material holding much entrained air. Whenever the temperature of the litter is higher than the air above it the entrained air, due to its temperature, will hold a large number of vapor particles and bring its vapor pressure in equilibrium with that of the remaining moisture in the litter and therefore retard evaporation from deep litter when left in a quiet state. Thus the heat required to maintain the process should be supplied from the air above the litter." This involves four things : (1) An insulated and water-proofed floor which is not appreciably affected by temperature or moisture from below. (2) Ceiling, wall, and window construction that will not permit of excessive heat loss. (3) A sufficient number of birds to provide animal heat or, lacking this, the necessary artificial heat to maintain as high an inside temperature as is consistent with good health and economy. (4) An adequate and controllable ventilation system for turnover of air. Are we giving ourselves a handicap when we continue to build poultry houses open to the elements and subject to the caprice of the weather? Are we fairly conducting feeding and breeding tests in poultry houses wherein we have no control over temperature, moisture and a i r ^ t h r e e most vital factors in determining the efficiency of human and animal endeavor?