Protein levels in a mixed ration depends on the level of protein for each foodstuff,then by the "parts" of that foodstuff added per the ration. For example corn has a 7% protein level,black oil sunflower seeds has a 17% protein level. A mix of 50% of both ingredients will give you a total ration protein level of 12%. But a ration of 1/3 corn and 2/3 black oil sunflower seeds will give you a protein level of 13,6%. A 25% corn,75% boss ration will give you 14.5% protein.