What do poultry eat anyway?

I have learned in the past that many different kinds of poultry eat different foods, such as my laying hens, they eat a mixed grain of corn and other nutrients that is compacted together into pellets its call Layer pellets. They eat this type of grain because they need a grain to help them with egg production, the hens also get to go outside and eat as many bugs and grass as they would like. My silkies and goose eat something totally different, they eat a grain that is the same corn mixture but broken up into smaller pieces and has nutrients for better feather and skin growth, its called Game bird crumbles. The silkies also get some extra things in their diet because they are for showing and need more to their diet. I first get a 5 gallon bucket and combine one bag Game bird crumbles, 1 cup crimped barley, 1 cup crimped oats, 1 cup wheat, 1/2 cup safflower seeds, 3/4 cup sun flower chips, 1/2 cup flax seeds, 1 scoop Manna Pro Sho Glo a equine supplement which helps with wight control, 1 tablespoon Brewers yeast and Garlic powder, 1/4 cup Red Cell and 1/2 cup vegetable oil. My goose gets just the Game Bird crumbles and geese also need to graze, so he gets free run of the lawn. These are some of my methods of feeding my birds and keeping them looking good all the time.