Here's why:
* Straw is the dry stalks of grain plants like wheat, barley, or oats. Horses can eat straw, but it's low in nutrients and mostly provides roughage.
* Alfalfa is a type of legume that's a highly nutritious hay for horses.
* Carrots are root vegetables. While horses might nibble on them occasionally as a treat, they're not a primary food source and aren't necessary for a horse's diet.
Let me know if you have any other questions about horse nutrition!