I have found a couple of holes like this over the past few months. In and around my chicken coop and run. Perfect little holes about an inch to two inches in diameter. The ground here is froze pretty hard. No dirt mounds around the holes that I can see. No dead or injured chickens. I am sure whatever it is is probably after the chicken feed.

Rats

That's what my guess was. I'll have to step up my removal program. Blind trail sets with zero jump's and #1 longsprings have resulted in nothing.

Rats are a challenge they are very intelligent critters I had some that moved into my coop one had a cropped tail so it stood out it took 6 weeks to catch that last rat in a snap trap with a fig bar piece mashed on the yellow trigger. Caught one in a 110 only because I pressured it with a flashlight and shot at it with .22 rat shot.

Bait them to the middle of the room then bust in during the night with a good light to access how many might be in there. Snap traps, tunnel traps, 110s and foot traps should work once my birds are roosted. I’d set right in the coop then remove the traps before sunup this works with rat shot also. Covering traps with a cardboard box with holes for them will keep the chickens out of the traps that way works.

How large of an entry hole do they need into a box? I tried weasel boxes (1 3/8 hole per WI reg's), but got nothing. Thinking they need a larger hole.

I hate Rats
I use Steve Albanos Wire traps in holes for rats, when they occur every few years

You get chickens ..you get Rats

My son mixes chicken feed with crumbled up rat bait blocks...make sure all the mixture is the same size..

Use a funnel with long tube....shove it into every hole you find...and pour contents down the funnel

I had rats move into my empty hen house from my neighbors chicken yard.... dug some pretty good holes, put the poison blocks out and viola!, no more rats....I don't like using that, but the darn things can breed new ones faster than you can trap them one at a time...

I alternate between 3 different poisons and shoot rats that learn to avoid the poison a few times a year. I also have outside cats that will kill full sized rats. There's always new rats coming in and/or a few rats that survive to reproduce. Rats are a never ending problem when you have old barns and a food source for them.

Keith

Pretty much anytime you feed animals outside, you’re gonna attract rats. Every chicken coup, pheasant pen, pig pen, and even dog kennels will have rats move in.

Funny story about rats at a pig pen. About 45 years ago, my uncle and I shared a pig pen and a large garden. There were always some rats near the hog yard. By mid September, the garden was wrapped up and we gathered up sweet corn stalks, potato and tomato plants, etc and had a couple big piles of them in the garden, near the pig pen. By early October, the piles were dry and my uncle and I tossed some gas on the piles to burn them. The piles lit quickly, and in a minute or two were fully engulfed. Soon, rats started running out from under the two piles. Dozens of them. A couple of them were burning, and ran into a field of dead goldenrod. , now the field was on fire from the burning rats, and the local fire company had to come out to get things under control.

Looks more like a chipmunk hole to me. Rats typically kick dirt out, no idea what 'munks do with the dirt but it's always a clean hole.
Where did the eggshell come from, did you drop it or did something drag it out and eat it?

never thought to use those on rats. im guessing you stake them well

I've killed 14 rats in my pole barn-trap shed since the beginning of trapping season. Five of them were roof rats (aka black rats) and the rest Norways. Three adult Norways and six half-growns. Most have been caught in 1.5 LS victors and a few in 110 conibears. Even two in conventional snap traps.

Scott, I'm guessing mole size, but do you use the mole size or gopher size for rats.

Keith

Rats are in many places yes they go for feed a easy meal but I’ve caught then in the middle of nowhere also.

Yep rats

Too bad they aren’t as cute as portrayed!
We see a handful a year at the clinic. The pets are friendly and intelligent, but as pests they sure cause trouble !