6 The University of New Hampshire [Bulletin 338 



air temperature on water consumjition was masked by the resulting 

 decrease in tgg production. 



Mitchell and Kelly (12) in studying- the ventilatitjn of i)oultry 

 houses found that at a tenij^erature of HZ" a four-pound White Ply- 

 mouth Rock hen consumes in twenty-four hours, 82 grams of dry 

 matter, and gives off 23ii Cal. as heat, 47 liters of carbon dioxide and 

 vaporises 164 grams of water. At a temperature of 50" the bird gives 

 off only 57 grams of water vapor per day. 



Their data showed that 4.2 cubic feci of air ])er bird per hour are 

 necessary to maintain a desirable limit of carbon dioxide. They as- 

 certained the amount of air necessary to remove moisture on the basis 

 of an assumed temperature within the house of 50" F. and a relative 

 humidity of 75% with a temperature of 15" F. and a relatixe Inunidity 

 of 80 % of the admitted air. The inside air, thev state, will thus hold 

 3.057 grains of moisture per cul)ic foot and the admitted air would 

 bring in 0.789 grains. Hence, there would be, in a pen of 200 birds, 

 7,315 grains of water per hour to remove. On this basis 16 cubic feet 

 of air per hour ])er bird would be recjuired to remove the excess mois- 

 ture. 



They also stated that there is some doubt as to the amount i^f 

 water that can be removed from the litter by ventilation. Much de- 

 pends on the floor temperature, the vapor pressure balance of the air 

 entrapped in the litter and that just above, and depth and kind of litter. 



Summary of this preceding literature shows that there is a great 

 deal of contradiction relative to wet litter in the poultry house and 

 the part it ])la}'s in the economic situation of the flock-owner. 



THE EXPERIMENTAL PEOT HOUSE 



The experimental work was initiated in November 1938 with the 

 construction of a litter "plot house" used to house representative 

 samples of materials suitable for use as poultry litter. This house 

 was built for study of the effects of outside air conditions upon the 

 samples of litter used. Twelve "plots" were built inside the house, 

 each 53^4' long, 2' wide and 4" deep. Each plot was filled 3^" deep 

 with a different sample of litter. 



The house was built upon posts with an uninsulated floor 2 feet 

 off the ground and exposed to currents of air ])assing underneath. A 

 water-tight roof \\'as constructed to protect the samples from rain 

 and snow. The sides of the house were of two layers of muslin, de- 

 signed to keep rain and snow out but to allow a free circulation of air. 



THE POULTRY PENS 



For the observation of actual litter conditicjns under practical 

 usage, ten poultry pens of the University Poultry farm were selected. 

 Eight of these pens. No. 11-18. inclusive, were located in a long com- 

 bination-roof laying' house with pens 18' x 22' in size with a similar 

 size service room. The other two pens. Nos. 1 and 2, each being 30' x 

 30' in size, made up a 30' x 60' combination roof laying house. 



Pen 11 located at the southwesterly end of the long house was 



