so do the man hours of time devoted to travel. These man hours of travel 

 time for the crew eventually increase faster than the man hours of load- 

 ing time decreases. (See Figure 5) . The larger the crew for any particu- 

 lar loading job, the faster the trucks can he loaded, and the larger the 

 crew, the greater the man hours of crew travel time for any particular 

 loading joh. So trucks and crew travel time become substitutes for each 

 other as crew size gets larger. The decision making problem involves 

 comparing the cost of the unproductive time of crew travel for addi- 

 tional crew members against the reduction in truck ownership costs. 



Another substitution relationship exists between shrinkage and crew 

 size. Shrinkage can be controlled within limits by increasing or decreas- 

 ing the size of the loading crew. This will change the length of time 

 birds spend in the crates while the truck is still at the farm. For in- 

 stance, if a fovir-man crew rather than a six-man crew is used to load a 

 190-crate truck (9,975 pounds of broilers) , it will take 1.54 hours longer. 

 This will result in additional shrinkage of 60 pounds. Valued at 16.0 

 cents per pound this costs S9.60. On this basis it would pay to use the 

 larger crew until the unproductive round trip travel time of the fifth 

 and sixth men cost S9.60 in wages. This would occur at a point 51.7 miles 

 from the plant.- Truck size is a substitute for shrinkage, because the 

 smaller the truck, with any given size of loading crew, the shorter the 

 stay at the farm. Truck size will not influence labor costs in loading 

 birds. 



Example of Use of the Assembly Model 



Assembly matrices, similar to the one shown schematically in Fig- 

 ure 3, were the basis for developing the least cost set of resources (men 

 and trucks) needed to assemble birds for each of the firm size and 

 production density situations. To illustrate the method used the follow- 

 ing case is presented. This case is concerned with element 3c from Fig- 

 ure 3 for the 5,000 pound per year density level using 190 crate trucks. 

 It involves the assembly of birds (14,400 birds or 960 crates) from Sup- 

 ply Band III with no reference to assembly of birds from any other band 

 by Firm C. With 190 crate trucks this is equivalent to 5.05 loads, which 

 requires six truck trips. 



1. Least Cost Complements 



Figure 4 shows the calculations for this case which were obtained 

 in the following manner: 



(1) The travel time required for the foreman and pickup labor to 

 reach the impound point from the plant was determined ( See Appendix 

 B and Appendix Table F-l.l and doubled to obtain round trip travel 

 time of 3.5 hours. 



(2) Added to travel time was the time necessary to load the num- 

 ber of loads specified horizontally in Figure 4. The loading time per load 



2 At a wage rate of $1.26 per hour for pickup labor, the $9.60 represents 7.62 man 

 hours, or 3.81 clock hours. The question faced is the distance the crew can travel in 

 one-half this time. This is worked out with the formula presented in Appendix B. 



20 



