Here an external link to a handy online Feed Calculator and a library of nutrition related information.

The system allows you to set-up a horse and a feeding plan for it. You then can identify where you meet the nutritional needs, where you feed too much, and where you should add more.

Have a browse and see if you like it. In case you want to sign-up for any of their plans, come back to this link to receive a 10% Discount voucher.