Dairyman's Square to formulate chicken feed

The following is how to determine the amount of energy and protein ingredients needed in the feed. The "equation" is called the "Dairyman's Square" (For more information on this, check out some of the poultry books in our new online store):


1. Draw a square
2. In the center of the square, write the protein content desired in the final mixture (such as 20%)
3. At the upper LEFT hand corner write "corn" and its protein content (9%)
4. At the lower LEFT hand corner, write "supplement" and its protein content (40%)
5. Subtract diagonally across the square (the smaller from the larger) and enter (in the corners) the results on the RIGHT hand side (20-9=11; 40-20=20)
6. The number at the upper RIGHT hand corner gives the parts of corn, and in the lower RIGHT hand corner you have the parts of supplement needed to make a mixture with 20 percent protein. Thus, 20 parts of corn mixed with 11 parts of supplement gives 31 parts of feed with 20 percent protein.
7. To convert this to a percentage basis, divide 20 by 31 and multiply the result by 100. The ending result, 64.5 percent, indicated the amount of corn that will be used. The supplement is represented by the remaining percent (35.5). And so...in a 100 pound 20 percent mix, there would be 64.5 pounds of corn and 35.5 pounds of supplement.