My birds won't touch the pellets, and it's really hard to eat for my bantam. Raised on crumbles, they stay on crumbles. And tend to like them a lot better. Though I have seen that with the crumbles, mine will only pick out the good corn and seeds and stuff, but won't touch the real crumbly parts, which makes me having to throw them out.
I found that when I use mash I get a lot of waste, when I use pellets the squirrels take them all, so I stick with crumbles and that also happens to be what they like the best!
I went to crumbles, I had to switch from hanging feeders to raised trough feeders but they aren't wasting it and the bantams like it a lot better than the pellets.