Cher, you might try using several circle layers of hardware 1/4″ hardware cloth, offsetting each layer to prevent snakes or anything else from climbing the pole under your stovepipe. I cut the circles to fit inside the stovepipe and mount it above the pivot screws. I use scraps of the cut cloth about 2-4 squares wide and bend the edge wires down to make a sharp and prickly surface on the lower circle. I am not sure if it is sharp enough to pierce the skin of a snake but it could be irritating enough to make it want to look elsewhere. It is tedious work to make the circles but it gives me a feeling of security with my stovepipe.
I have also heard of using a scrambled mesh of chicken wire wrapped around the pole inside the baffle.
David
Stafford, VA