Prevent nuisance opossums from entering structures by closing openings to cages and pens that house poultry. They are not strong, so 1/4-inch wire screening or simple 1/4-inch plywood is more than sufficient to stop an opossum.
Use electric fencing (if legal in your area) on top of fences to prevent opossums from climbing over them. Make sure the wire is tightly stretched and situated near the top of the fence 3 inches (8 cm) out from the mesh. Fasten garbage can lids with a rubber strap.
Resources: (online)
Opossum