158 COMMERCIAL POULTRY RAISING 



inward end, which releases the cleat " D," and the door flies open. 

 This may surprise the fowls at first, but they soon become ac- 

 customed to it. In fact, they will actually learn to operate it, 

 just as they learn to operate an automatic feeder. 



Thus, Mr. Poultryman, you can finish your nap in peace; let 

 Biddy do this early-rising work. 



It would be impracticable to make the adjustment of the 



(Courtesy C. L. Opperman) 



Fig. III. — Serviceable, inexpensive colony house, constructed of rough lumber 

 covered with patent roofing paper. 



door so fine that the weight of a month-old chick could depress 

 the platform; but this is not necessary. Chicks move about in 

 crowds, especially when they are trying to get out of a building. 

 Very good, the crowd passes across the trigger platform — and the 

 trap is sprung ! Liberty ! 



In connection with the early-rising door it may be desirable to 

 make the exit as near proof against raiders as possible, even in 

 the daytime. Rats do most of their marauding at night, under 



