Poultry forage seed balls!

Paul is asking for new ideas for seed ball ingredients -- what about something that you could toss in the area where your poultry forage to put some extra nutrition, excitement, and diversity in their diet?

I've heard mixed reports on the success of large seeds in seed balls, so I'm sticking to the smaller seeds here:

Dwarf essex rape
White proso millet
Golden flax
Salad mallow
Purple top turnip

This mix could be any number of plants that chickens find delicious...but that's an example!