Can anyone give me information on alfalfa hay and oats hay?

Depends on your market as far as which will make more. Often either can lose money. In forage, quality is king. Or at least what the customer thinks is quality. Oats is much easier to establish and costs less to do. Alfalfa is more difficult. You will harvest the oats once, preferably right after heading before the oat seeds develop much. Alfalfa you will harvest repeatedly, probably every 3 to 5 weeks for several seasons. You will end up with more from the alfalfa. Generally for small acreages, you will want to do small square bales, idiot cubes they are called. If you are selling the teenagers for their horse, you want the smallest bale you can get, they will like a smaller, lighter one better than a big heavy one, and their horse is fat anyway. Many markets want oats straw for bedding and will pay as much for that as the oats hay, plus they will also buy the oats grain. That might be better for you. If you are surrounded by urban neighbors, expect to get threatened, blamed and even sued whenever you do something. You might not, but don't be surprised. For 20 acres, you are probably going to make more renting it out than farming it yourself. The equipment costs are so high unless you buy old junk that really should not be used anymore. Marv