I've never mixed my own but I've come across this method for figuring the proper proportion of protein in a few different books that I've read. Hope it helps.
PEARSON'S SQUARE
From Colorado State University
For mixing a GRAIN and a PROTEIN CONCENTRATE
to get a desired protein percentage
(see diagram below)
Draw a square and put the desired protein percentage in the center. Example: "finished feed 16%".
Put the grain in the upper left corner as a protein percentage . See the "Protein in Chicken Feeds" chart (below) to get amounts.
Example: "wheat 12.5%".
Put the grain in the upper right corner as parts to mix .
Example: "wheat_________ parts".
Put the protein concentrate in the lower left corner, as a protein percentage.
Example: "soybeans 37%".
Put the protein concentrate in the lower right corner as parts to mix.
Example, "soybeans ________ parts".
Grain:===========================================Grain:
wheat 12.5% ________ parts
| * * |
| * * |
| * * |
| Desired * |
| protein amount: |
| 16% * |
| * * |
| * * |
| * * |
| * * |
| * * |
Protein concentrate:===============Protein concentrate:
soybeans roasted 37% _________ parts
Now subtract diagonally through the center, from corner to corner. Ignore changes of sign.
Going from top left to bottom right, 12.5 minus 16 equals 3.5. This number goes in the lower right corner.
Going from bottom left to top right, 37 minus 16 equals 21. This goes in the upper right corner.
The result is 21 parts of wheat to 3.5 parts of soybeans.
