Trust me, the rats dig, mine do, I have them here like stink on poop!
I shot at 9 yes that's right NINE tonight and only killed one, for every one rat you see you can bet there hundreds HUNDREDS more! I killed one in its tracks its hard to hold the pellet gun and a big maglite and try to get a good shot on them in the dark.
Mine were going through the chicken wire at first, crawling all over the top of my coops, so gross we would catch a few in there every once in awhile and always had a shovel in hand to bash them over the head with. We had one try to go through the wire and got stuck and died, I had to cut the wire to get it out.
They haven't been going through the wire now, maybe babies but that's it, now they dig tunnels ALL OVER around the edges of my coops, I put bricks rocks bury them back in and they just re-dig or dig around or dig a little further to get past the bricks and rocks.
How big was the hole? The hole I have a about the size of a large gopher hole, and some bigger, you know how big opossums are, you think that's what it could of been? They do not usually dig that I know of, and I have yet to loose birds to them, but I have found them around, I read one place they eat rats and bugs and eggs, sometimes our birds. I have lost birds to rats and raccoons, they (rats) were eating my quail (not my buttons, my coturnix), that's why I cant have quail anymore (I sold my buttons before they were killed too), and just a few weeks ago they killed my sons show call duck that's the first big bird they have killed and I fear not the last.
I tried putting wire down on the bottom of my quail pen sitting on the floor thinking that would stop them, nope, that just made them tunnel under the pen using the wire as the top of the kennel i used 1/2 x 1/2 cage wire, they still grabbed the poor things through the wire and killed and ate them through the wire.
I keep free choice food out there for my birds and rats now they seem to want the feed more then the birds and that's the only thing i can do right now to keep them away from my birds, i was taking the food away at night and that's when my 5 year olds duck was killed and 3 others wounded by the rats. They kill and try to take the bodies down the holes with them.
I have moved half of my flock out, put poison out, and moving the other half this weekend, making new pens off the ground in hopes i can take out a good portion of these rats and protect my birds when they come home, i am missing them like crazy its like missing my kids almost.
This house has been here over 40 years and it has old sheds up of my in laws, there is an old abandon house next door that god only knows what lives in there, I really hope I can get these under control. I can not live without my birds!!
Sorry for the long post but I hope you can find a way to get the culprit under control.
You can buy bait stations or make your own at some feed stores, put a trap in there and whatever you think they are coming for, I have tried fish, peanut butter, crunchy and not LOL with some marshmallows and number of other things but what gets mine the best is the poultry feed, I set it inside the station in the dishes the rats have to go over the trap to get the food and they get snapped, but they are smart!! They will push dirt leaves feathers and such in the holes to tell others not to go in there, they figure it out that's not a good place to go and will avoid them all together, I have to rotate my traps around every week.
Good luck everyone who's having problems, I feel for you!!
If it was mice would still sick me out, but I do not think I would loose birds to them??