I would say there are MANY animals that can get through chicken wire. Essentially, chicken wire will keep your chickens in, but will not keep anything out. I'd recommend using hardware cloth or welded wire. I use hardware cloth for all windows and the lower few feet of the walls of the run so that nothing can reach through. I used the welded wire on the top of the run and roof.
YES..foxes, Dogs, Raccoons, opossums can get through chicken wire, and they can dig under it too. My suggestion is to use galvanized hardware cloth (it can be kind of expensive, but worth it). Put this around the chicken coop/Run....and ALSO put is around the bottom on the ground (like a skirting) then secure skirting with bricks or i use cement blocks. this will help turn away animals that are trying to dig in (because their claws will keep getting caught on the wire).
We did bury the chicken wire for digging animals, but I didn't know if it was safe to leave the coop
door open at night in the summer. Do you think if we put a foot or two of hardware cloth around the
base of the run we would be alright? I wonder how long it would take an animal to chew through the chicken
I wouldn't consider them safe at all. What are the walls of your run made of? If your run is made of anything climbable (chainlink, wood, chicken wire, etc.) and not covered, predators like possums and coons can climb it just like climbing a ladder. Smaller critters (young possums and skunks) can come through chain link. Leaving the door open at night would also leave them vulnerable to owls and early-morning hawk attacks. Can you cut a window and fasten the small mesh (hardware mesh / wire) over the window with screws? (most recommend running long wood screws through a firring strip and the mesh, fastening it to the window framing securely).
The run is completely covered and secure, but with chicken wire.
We have a hawk's nest in a water tower nearby so we have to keep them
covered, but I was hoping in the heat we could allow them to get out
of their coop before we get up...but I guess not. Thanks for the info.
If this helps - I had coons tear open and get all my chickens thru chicken wire. Wasn't really set up to replace wire so instead I have a hot wire (electric fencing) that runs about 3 inches from ground on the outside, then about 12 to 18 inches from ground, and along the top. Cheap to run, doesn't look too bad, and not any intruders and the low wire seems to stop digging. Have caught coons and possums in live trap outside the run since then but chickens have stayed safe. Have been told this would even keep out bears. Just FYI in case this gives a quick solution.