Recommend Large flake food

Hi:

I have Severums and Bood Parrots (separate tanks) but they have one
thing in common and that is they will only eat certain sized food. I
like to feed them flake food several times a week which rarely happens
because so far all the brands of flake food I've purchased (clearly
labeled LARGE flakes) have very few large flakes left by the time I
get it home. My blood parrots have a really hard time eating or that
might be catching food. They won't even go after it if it's not a
certain size so can anyone recommend a LARGE flake food that is still
in flakes not crumbs. Or is there something out there like SLOW
sinking pellets. I need advice on foods to feed these guys. My
Severums are just plain picky. If they had their way they'd eat Krill
and peas 3 times a day for the rest of their lives. Silly fish.

Thanks, maibit