I'm going to try to simplify picking out hay a little into a beginners lesson. Smell it. Does it smell good? Does it smell dusty, moldy, like it has mildew? Should smell sweet and good. If the smell does nothing for you either way, it's probably ok hay. I like it to smell sweet. And look a bit green still if it's coastal (which means it was cut from Coastal Bermuda grass primarily) or of course alfalfa. Even nice straw has a sweet smell to me. So there ya go. Smell it and look at it. You want it to smell good and not ugly brown and full of stickers.