I use a supplement called buck grub. I don't actually use a corn feeder. my feeders are more of an elevated livestock trough with a roof. i mix 2lb of corn with 2lb of sweet feed and a lb of the buck grub in the mix. the deer are absolutly loving this stuff, and i am pulling deer in from other areas as well. from what i can tell buck grub is rice bran with some minerals mixed in with it. I also plant some crops in the area of my feeders as well. Yes deer do love mustard greens too. if you know someone who has a feed mill, ask them to get you a sack of rice bran and give it a try.As for the buck grub, it ran me about $25.00 for a 25lb bag, but i found that a little of it in my feed mix goes a long way. I can stretch 1 25lb bag of buck grub per 150lbs of corn and feed. I have tried other supplements before and had no sucess with them, but i have been real happy with the buck grub. Hope this helps.