We need also to be cognizant of the quantity and quality of feed the horse is ingesting. We might, for example, have a group of horses on a winter pasture that has been saved for just that purpose. We look at it daily and it appears that there is grass present. Just a glance isn't enough. The pasture should be walked.
Horses are picky eaters.
They don't like to consume grass where feces have been deposited. Thus, we might be looking at a pasture that appears to have a plentiful grass supply, only to find upon closer examination that much of it is in little islands around piles of manure and the horses are passing it by. Hay quality also is highly important. Green, leafy hay is a must. On the average, a 1,000 pound horse will require about 15 pounds of good-quality hay per day.