Sad but True. My existing set up deters almost any other threat to my birds, but the possum is 'stupid enough to not take heed, and like a rat, can get any any hole it's head can get thru, making young 'possums a perhaps greater threat at times.
My usual joke lines are, "How long you fatten them up?" or " Thar's sum gud eatin' thar, if ya fix it rite, boy !"
Your recipe doc? , LOL