Are they on a pellet diet now? If not, it may take a few tries to find what they like. I’m a firm believer in feeding “the best pellet that they will eat”.
A couple of mine eat Zupreem natural and have done well on it. None of mine would eat Tropican when I tried to feed it - but I have heard that they are a good pellet. Two of mine will eat Roudybush, and one will only eat Lefaber pellets. I have also tried a couple of different Harrison’s pellets, which mine won’t touch - and I used to feed TOPs until something changed in the texture and now none of my birds will eat them.