Since I don't have any chickens or bunnies, I can offer no possum advice about those. Once in a while a possum will wander through the property, and they usually don't bother me or the bird feeders (which are hung high on wires). What DOES bother me is those times the dog spots one up in the tree and proceeds to engage in a bark fest that can go on for hours. The possum will calmly stare down, totally unperturbed. When my patience is at an end, I'll go out and throw a rock at the possum. Sometimes it works, sometimes it doesn't. My aim isn't all that good. I've learned over time that possums are not easily intimidated.
Hope all of your animals are okay.