FEED LASTING TIMES

.2 lb of
¤ Flaked Corn
¤ Bran
¤ Chaff
¤ Oats
¤ Flaked Barley
Lasts 1 day

.1 lb of
¤ Sweet Feed
Lasts 1 day

.04
¤ Salt Block
¤ Mineral Block
Lasts 1 day

.1 bag of
¤ Carrots
¤ Apples
Lasts 1 day

.2 of a hay bale of
¤ Regular Size
¤ Round Size
Lasts 1 day

All these numbers are for only ONE horse. All you need to do is multiply the amount that will last one day by the number of days that you want your feed to last. If you come up with a decimal number, round it up or down. If you're ordering for more than one horse, multiply the end number by the number of horses you're ordering for.
A little tip: It's easiest to order feed for the rest of the year. Below is the number of days until December 31.