Then they probably arent getting what they need unless you've had your hay tested.
The feeding directions are there for a reason. The min amount to be fed is what is required for the animal to meet it's nutritional requirements.
Something else the horse owner can do, is call the 800 number and ask to speak to the equine nutritionist.
I have to drive 38 miles to buy EquiPride (which is now way too pricey) or McCauley's M-10 Balancer, both of which are soy-free and grain-free. Except for distillers grains, which have had the sugars extracted by whiskey makers, therefore ok to feed to sensitive horses.
I found out AFTER I bought the first bag of McCauley's that I had to pre-order a month in advance -- that made me really happpaaaaay
Anyway, I called McCauley's and explained my fear of running out of the M-10 for that soy intolerant horse ^^^^mentioned - lol lol
He asked me about hay, how tall, how heavy, breed & age the horse is, and also the horse's daily routine, which is nothing but eat grass all day
After getting all that information, his very kind reply was "---- to stretch your bag out, you can cut back to 3/4 of a pound daily until the new order comes in. Based on everything you've said (me), this horse will get all his nutrients on one pound daily ---- and be sure you measure that---".
The instructions on feed bags are great guidelines but they are a generic, one-size-fits-all.
If somebody needs to really split hairs, I have yet to talk to any company's equine nutritionist that wasn't willing to jump thru hoops to help the horse owner figure out what the correct amount of feed would be for each horse