30 N. H. Agricultural Experiment Station [Bulletin 303 



Many of the exact requirements or specifications to accomplish the 

 above have never been established and are not available as definite fac- 

 tors by which the equipment, could be measured. Part of the work, 

 therefore, has been to attempt to determine what some of these factors 

 should be in the absence of data on the basic requirements of poultry. 

 Much valuable fundamental material of this type awaits determination 

 and will be essential to the satisfactory development of equipment. 



General Summary of Four Years' Work 



Several factors were studied and reported in Station Circular 46 

 of the New Hampshire Experiment Station relative to the heat re- 

 quirements for electric brooding of chicks. During the subsecpient 

 years of 1935, 1936 and 1937 the following subjects have been added to 

 the study: (1) Floor insulation. (2) Labor and fuel costs for coal 

 versus electric brooding. (3) Application of heat under brooder. (4j 

 Relation of house floor area to brooder size. (5) Prevention of floor 

 drafts. (6) Extended brooding period. (7) Effects of power ventila- 

 tion. (8) Chick movement, (9) Physiological needs of chicks. 



1. Electric brooding is practical and can be carried on under very 

 severe climatic conditions without auxiliary heat or excessive mortality. 



2. Necessary high cost of application and lack of value from the 

 insulation of walls and ceilings in houses used for electric brooding in- 

 dicate its use to be unwarranted. 



3. Although the results of our tests indicate that 1" of insulation 

 enclosed in a water proof bag and placed between two layers of wood is 

 the point of diminishing returns from floor insulation, there is nothing 

 to indicate that a double wood floor with a disc of 1" insulation board oi- 

 its equivalent, properly waterproofed and slightly larger than the 

 brooder, placed on the floor under the brooder will not be just as good 

 as, or slightly better than, built-in insulation, and is certainly less ex- 

 pensive. 



4. A comparison of labor and fuel costs for coal and electric brood- 

 ers indicates very little cost differential between the two methods. 



5. Under cold weather brooding, when litter changes are neces- 

 sary, it is recommended that the new supply be pre-heated before being 

 placed in the pens. 



6. Increasing the square area and cubic contents of a brooder by 

 the addition of extension rims and extra curtain, without changing the 

 chick load or heating element, was of material benefit in stabilizing tem- 

 perature control under the brooder. 



7. It is important to establish values for air exchange under the 

 various types of electric brooders. 



8. No difficulties in the management of chicks were encountered 

 in a prolonged brooding period of fourteen weeks as long as the cock- 

 erels were separated from pullets at six weeks of age. thus reducing the 

 number of chicks approximately one-half and compensating for their 

 increased size. 



