What to feed horses?

Hi everyone. Well I'm hoping I will be able to have a few horse projects in the future, but i'd like to know everything I can before I even think about getting a horse. My main "issue" right now is feed.

I have read that you have to feed both hay and grain to a horse, but I'm not sure how much. Most likely, any horses I would have would be warmbloods/thoroughbreds or quarter horses/paints if this helps. How exactly do you feed? Hay and grain in the morning and at night but how much each time?

Also, how about if there are pastures.. how would I use that to my advantage, as in when would they go in/out, and if they still need the hay. I would probably bring them in for the night, and take them out in the morning until I come back in the afternoon.

Also, how do you buy your feed? Lets say I have 4 horses, how much hay do I purchase at once to last as long as possible? Also grain??

Thanks in advance!

I have 2 horses, 2 ponies, on a lot with no grass.
They go through a round bale of fesque/orchard grass every 2 weeks.

We feed to keep weight on.

I'm not the primary feed person, but I know you do not have to grain, unless there is a weigh issue/they need a supplement/they're performance horses.

I don't have any pasture here in southern Arizona. I feed my two horses bermuda hay. Alfalfa is available here, and cheaper, but they get too rowdy on it. A bale weighs around 80 lbs, and won't quite last a horse a week. I feed them hay twice/day, and the meal in between is a coffee can of complete feed pellets. During the winter, I have to up the feed a bit, although it rarely hits 20 deg where I am at. They are both Arabians...well, one is 3/4 Arabian.

I don't do the feeding at this moment, due to having to board. But that said my BO feeds the horses 2 main meals morning and evening, and a smaller meal in the afternoon when she gets home.

My horse gets 3 sections of grass mix hay, am and pm. 1-2 sections in the afternoon, depending on how cold it is! She also gets a 2 qt scoop of alfalfa pellets in the am. She gets another scoop on days I ride her hard after our ride.

Free choice hayis always the best place to start ..

You want to avoid grain based feeds

I feed a ration balancer(vitamin/mineral supplement ) designed to balance my hay type and add calories with hay pellets or rice bran as needed