Just my personal opinion on Smartpak comes with a story!
So I bought smarthoof for my mare, at first she stuck her nose up at it but realized it wasn't a choice. Just bought Smartdigest for another mare, eats it perfectly. Smartbreath for my stud colt, eats it perfectly. Darkhandsome for my gelding.... won't eat it. What did I do? Tied his butt up and made him eat it. Guess different horses have different thoughts on it. Though the mare on smartdigest eats anything and everything... lol. Smartpak is very helpful, you will find them the same as I did.