If you're going to do this you should do it like JD3006 did, in February or earlier. The deer, does in particular, really like and need these supplements in the spring when they're carrying and giving birth. They ususally slack off on it during the summer but will still visit it year round. I've seen deer just dig cavernous holes at old mineral licks. When I lived in Georgia we had a couple that would hold a small car.