If you can't get a feed that is formulated for geese/waterfowl then a mixed flock feed like Flock Raiser is fine. If they graze they will get most of their nutrition that way while there is grass available. Some feed, scratch and/or cracked corn on the side plus treats like Romaine Lettuce and watermelon and they will be happy beyond imagining.Mine are too old for chick starter, besides regular scratch and then grazing is there anything else they like to eat?