I just discovered the awesomeness of SmartPak too! Very cool, easy to work with and not even that expensive.
Signa (5yo mare): SmartCalm (she's also called "crazy horse"), SmartMare & SmartGut. She's been on these for 1 month now and I think the SmartMare/SmartCalm is helping but I need to give it more time to be sure.
Magic (30yo mare): Smartflex Senior & Farrier's Formula DS
Rizer & Frankie (minis): Equishine (multivitamin since they don't eat much grain)
I used to be anti-supplement but obviously that changed at some point...