straw has a bit more stalk of the wheat and barley plants and different types of hay like alfalfa are available depending where you are. but those other types of hay are for livestock like cows through my grams used alfalfa hay for the nest boxes year round but for the most part yes it is the same thing.
Straw and Hay are not the same thing!!
Straw is the dried stalk of cereal grains such as wheat, oats, rye, rice and barley after the grain and chaff has been removed.
Hay is legumes, grasses such as Coastal and Bahia which is used for feeding livestock.
Hay is not preferred for yardbirds because the grass is typically too long and can get stuck and choke a chicken.
Personally I would only use straw for nest boxes only and not for bedding or in the run due to fact it can get moldy and takes too long to break down. JMHO
David