Let's say a horse is around 16 hands, and he/she is on pasture most of the day; ridden 4-5x a week. How many lbs of hay a day would you think they would need?? Because I have read about 16 lbs a day for a 1000 pound horse, but if he horse is on pasture is it really necssary to give them that much?
It really depends on the individual horse's metabolism, and how much pasture you have. There is no set amount, you just have to experiment and see what works for your individual horse. The horse in my avatar is 16.2-16.3 hands, on 6 acres of pasture 24/7 and I haven't fed him a bite of anything since April. He's purely on pasture, and water of course, nothing else. He get's ridden 4-5 times a week, and ridden hard. And he's currently around 1300 lbs and overweight. 7)
(sorry thought of another one) Some people say that a horse only needs grain if they are lactating or a hard keeper, old or in hard work ;something like that. But if the are not old and ridden 4-5 times a week, do they need grain??
Again, as mentioned above, it depends on the individual horse. Out of my 5 horses, only 2 get grain. One is my mare Freyja, and she IS lactating and nursing 3 month old Fiona, as well as being a rescue who was underweight from the get go. She does appear to be a bit of a harder keeper, though I think once she is no longer nursing I might be able to wean her off feed and only grain her in the winter. The other one currently on grain is my yearling colt Finn, who is currently going through a growth spurt, so he's getting just enough grain to supplement his growth while he is young. By the time he reaches maturity I don't expect to need to grain him. My gelding Claymore, and my pony Misty never need a bite of grain, summer or winter.