So, here's a thing I learned. I didn't buy "crumble" even though that's what I was told I was getting at the cashier's desk. What I actually bought was "crumblet" which is pelletized mash. (but somehow not actually a pellet food - confused? me too). And apparently my chickens think that crumblet is nothing even remotely related to food. Unless I feed it to them in a pan and add water. Then they think it's the best stuff ever.
I discovered all this because I went to the local TSC and carefully read the feed bags (that's not an option at my local feed store - they keep their stuff in the back and bring it out to you). When I found a picture of true crumble on a bag I realized the difference between the two forms. And I bought a bag to see if it would actually make a difference to the most important part of this equation - the birds.
Ha! Totally made a difference. They like the crumble (larger, natural-looking pieces of food versus a compressed pellet) just fine. As a bonus, they're significantly neater in their eating of it than they were with the mash. So I'm now a crumble convert. I'm not wasting the crumblet though - they still get that as their morning and evening treat in the pan with water.
A win all the way around.