I had the exact opposite problem, I used Dumor and thought maybe to change them to Purina. The bag of Purina I got was 90% powder!and if you have a local TSC, their "Dumor" brand now has a 20% protein as well, I believe. Its a little cheaper, like buying "store brand" at the grocery, but the comments here on BYC about it have not generally been positive. Lots of complaints aoubt it being powdery.
Of course, if you serve as a wet mash or fermented feed, that's not an issue.
if you have local mills, decent chance a 20% feed is available to you at a decent price.
and whatever you decide, fresher is better!