The measure amounts to feed each of the horses and the chickens is on the green board in the tack room where Tex is working. Each horse is listed by name and you have to follow those amounts exactly.
Under the green board there are five boxes where the different feeds are kept - he box on the left is oats, the next is pellets, the third is corn, the fourth is cow feed and not used and the last is chicken feed. Put the pail on the scale and (as an example) if the directions are -
3 oats 11/2 pellets 2 corn
First use however many scoops it takes for the scale to move to 3, then however many scoops of pellets for the scale to move to 41/2 (3 + 11/2 = 41/2)and last add however many scoops of corn it takes to move the scale to 61/2 (41/2 + 2 = 61/2).