But the hardness of feed pellets directly affects the appearance and the production property. 
So controlling feed pellets hardness is a problem the feed manufactures face.The factors affecting the hardness mainly include
the feed ingredients grinding process,feed ingredients mixing,water
adding and steam modulating process, post curing technology etc.

The pulverization fineness of feed ingredients plays the decisive role in feed pellets hardness. 
Generally speaking the finer the particle size the better the starch gelatinization. 
Fully gelatinizing the starch can ensure the good bonding effect of feed ingredients which makes the feed pellets not broke and have good hardness.