how can we determine the mixability of a mixer in feed industry?

Answer 1

You can do some experimentation. For example, put two different grains in a vat, and mix for specific periods of time (5 seconds at a time). Sample the vat in a couple of places and count the type of one grain, and then the other in the samples, and record the data.

Do this with a couple of different mixers and you will see some statistical trends that will help you.

Mixer vendors may have a standard or a rating they can supply in an attempt to discriminate their product from others.