Some feed ingredients have a good impact on pellet quality,while others could adversely affect the quality. Unfortunatel,corn-soy diets are not the ideal diets to achieve the desired pellet quality. 
Dietary inclusion of wheat grain or wheat by products(wheat midds, wheat gluten) can increase pellet durability,because of the high protein (gluten) and hemi-cellulose content of wheat in comparison
to corn or corn co-products. Similarly inclusion of oat as a partial substitute of corn can increase pellet quality.

We can rank feed grains according to their positive impacts on pellet quality from best to worst as followings:

oat,
wheat,
barley,
corn,
sorghum.

It was previously known that starch and its gelatinisation is the most important factor for achieving the desired pellet quality.