Here is something I found though, this website - How Much to Feed your Horse?
...suggests how much grain to feed your horse once you put in their body weight, workload and body condition. Last time I measured my gelding, his body weight was around 960, he might be 1000 lbs now. I do light work with him, and his body weight is normal. The calculations though say to feed him 2.3 kg/5 pounds of grain! I measured my grain on my kitchen scale, and 5 pounds is 16 cups! Wouldn't that be too much? I have an 8 quart feed bucket, and the suggested amount of feed almost fills it full. Plus since he's an Arab, he does tend to get pretty hot with too much grain.
I just want to feed him properly, but I'm concerned and a little confused, how much is too much, and how much is too little? Any advice would be so greatly appreciated!