Any bag of grain with 50% dust is no good. Oats are not a good choice, although a limited amount can be fed. They have difficulty digesting it if there is a hull on it. The extra fiber of oats can help with gut health, but in limited amounts.

Barley can also be an issue - depending on the variety. Canada and Europe have used barley based diets (instead of yellow corn) for decades. So watch what variety it is. Some varieties require the use of feed enzymes to break down some of the anti-nutritional factors in barley.

Ok, then what grains should they eat?

When included in a complete feed (or fed as a grain with a nutrient balancer with protein, vitamins and minerals) they can use a mix of corn, wheat, barley and a small amount of oats (or naked oats) - just need to be careful with the oats and barley. More so with the oats than the barley. Other grains can include sorghum. 

See CEREALS IN POULTRY DIETS – Small and backyard poultry for more information on the types of grains recommended for poultry.

Remember that if feeding whole grains, the birds will require grit to help with the digestion.

The grains supply primarily energy and a supply of protein, minerals, and vitamins is also needed.