342 ENGINEERING ON THE FARM 



board, which should be 2 feet 6 inches above the floor. 

 Dropping board and perches should be made movable to 

 facilitate cleaning. Nests should be provided at the rate 

 of one for three to five hens and should be 12X12X16 inches 

 in size and at least 12 inches from the floor. The roof may 

 be of any type desired, but should be tight. 



SILO 



General considerations. The value of the silo on the 

 modern stock farm has been thoroughly demonstrated, and 

 since a discussion along the line of its advantages falls 

 within the province of animal husbandry, it will not be 

 considered in this chapter. The method of silo construction 

 is a question upon which users disagree. It is usually found 

 that the owner of a silo is satisfied with the style of con- 

 struction which he has used and would not be satisfied with 

 another. There are a few fundamental requirements which 

 are necessary for any silo, regardless of the materials of 

 which it is to be made or local conditions. It should be 

 practically air-tight, since cracks and leaks in the walls 

 always produce spots of spoiled silage. Silo walls should 

 be of impervious material, as it is essential that moisture 

 be retained, and the inside walls of the silo should be smooth 

 in order that friction may not prevent silage along the wall 

 from packing. The silo walls should offer as much protec- 

 tion from feeezing as is possible and must have sufficient 

 strength to prevent bursting when filled. Other charac- 

 teristics relate to first cost, resistance to fire and wind, 

 durability, and conformity in appearance to the other farm 

 buildings. 



The economy of the silo is for herds larger than 10 dairy 

 cows or their equivalent. The requisite of a good silo 

 is air- tightness. In severe climates freezing will occur in all 

 types of silos. No one type can be recommended in preference 

 to all others. The size of a silo depends upon the quantity 

 fed per day and the length of the feeding period. Reinforce- 

 ment is necessary to resist the bursting pressure. A tight 



