28 The University of New Hampshire [Bulletin 338 



pheric moisture and (5) snow or rain storms beating into pen. It does 

 not seem probable that moisture is deposited from the outside air 

 directly, although this air, no doubt, controls certain conditions re- 

 sulting in high litter moisture. Winter outside air is usually lower 

 in temperature and humidity than the poultry house air and therefore 

 could not add moisture to the poultry pen from its own mass. Cold 

 air entering a poultry pen can, in mixing with warmer, more humid 

 air, chill it below its dew-point and cause the precipitation of some of 

 its moisture. 



The outside air does aid removal of moisture from the poultry 

 pen. During the night when the front curtains are partially or entire- 

 ly closed the humidity increases in the pen to nearly 100 per cent. 

 Also lower temperatures at night serve to increase the moisture con- 

 tent of the air. Just as soon as the curtains are lowered in the morn- 

 ing the pen humidity drops sharply. These factors indicate that dur- 

 ing the day conditions are optimum for the removal of litter moisture 

 from the pen. The drier outside air enters, mixes with the more 

 humid air of the pen, decreases its actual moisture content and moves 

 it out of the pen through the ventilating devices. The higher temper- 

 ature of the poultry house favors evaporation from the litter and the 

 humidity of incoming air being lower, allows this air when warmed to 

 absorb more moisture. 



While the plot house litter moisture curve remains steady and 

 shows no particular trend, the poultry pen litter moisture shows a de- 

 finite seasonal character. The litter in the poultry pens carried about 

 twice as much {2fd'/c) moisture through the summer months as did 

 that of the plot house. With the approach of less favorable winter 

 weather conditions the moisture content of the pen litter increases, 

 reaching a maximum of about 50 per cent by weight in February and 

 early March. Following this period and with the improvement of 

 weather conditions of the Spring there was a gradual decrease of litter 

 moisture until the latter part of June, when it again averaged about 

 20 per cent. Under-floor heat is conducive to dry pen litter condi- 

 tions. 



Peat moss was found to possess the highest absorptive capacity 

 for moisture of any of the litters studied, and also the greatest reten- 

 tion of this absorbed water. Sand and gravel showed the least water 

 absorptive capacity. 



It was well esta]:)lished, as noted in Figure 1. tliat additions of 

 fresh, relatively dry litter to poultry pens during the winter months 

 do not result in continued dry litter conditions. The newly added 

 litter picks up moisture rapidly and in a few weeks reaches the mois- 

 ture level of the old litter. 



There appears to be no relation between percentage of ^^^ pro- 

 duction and percentage of litter moisture. The mortality of housed 

 layers is not directly related to litter moisture condition. 



Records indicate a water consumption of approximately 22.6 gal- 

 lons per bird per year. Since water spillage by the birds was noted as 

 a cause of wet litter a cone-shaped device (Figure 8) was constructed 



