Mouse problems - How are they getting in?

[Falcon Chickens]

So, I researched for probably a year before building my coop/run, and I have always thought it was as secure as Ft. Knox. The floor has hardware cloth, all of the walls are hardware cloth, all of the windows and vents are hardware cloth, all of the trim is caulked, etc. Never had any issues until my neighborhood recently started clearing a nearby field for new construction, and now the field mice are everywhere. Started seeing mouse poop in my run, so I repointed my night camera to that area, and we're seeing several mice running around in the run every night. I've gone back through the whole coop/run looking for anywhere that they could be getting in, but can't find anything. There is no sign of digging/tunneling; there is no sign of wood being chewed. They are avoiding the snaptraps that I've set (I put them in the run after our girls have gone to the coop for the night, and remove the traps before the girls wake up). They've avoided all of the snaptraps that I have set around the the outside of the coop/run.

The only way that these things can be getting in is by going through the 1/2" x 1/2" hardware cloth, which just doesn't seem possible. Anyone else experienced this?

I don't know what to try next. To change to 1/4" x 1/4" hardware cloth would be a major task...nearly impossible.

 

[tcstoehr]

I wouldn't bother replacing your 1/2" HC with 1/4".
My first suspicion is that they are squeezing under your run fencing. But I have no idea how your run is constructed.

 

[aart]

Maybe try a bucket trap?

Set your snap traps with the baited end against a solid flat surface.

 

[Naser]

Get mouse proof feeder and they will go

 

[MeepBeep]

Are all the doors and windows when closed, 100% sealed? If there is for example say a gap around a door that is enough for a mouse to squish through...

Some pictures would be helpful...

 

[bobbi-j]

A mouse can squeeze through the smallest of spaces. I have a feeling your suspicions are right - that they're getting in through your hardware cloth.

 

[RWD]

What are you baiting your traps with? Peanut Butter works best. You cannot keep mice out of a chicken coop, because there is so much excess food around. Traps baited with peanut butter has worked for many many many years. They don't eat much.......

 

[MeepBeep]

A mouse can squeeze through the smallest of spaces. I have a feeling your suspicions are right - that they're getting in through your hardware cloth. 

Yeah the general rule when 'sealing' up a structure is that if you can slide a common wood pencil into a hole mice can get in through that same hole...

 

[enola]

1/2 x 1/2 hardware cloth will not keep mice out. Well maybe a pregnant mouse......... If any cracks are big enough to place a pencil in, a mouse can squish himself through it! I feel your pain.

 

[Falcon Chickens]

Thanks for the responses.
We've been having some snow dustings the last couple of days, and I've been trying to find their footprints in the snow to see if I can isolate how they're getting in, but haven't had any luck. That leads me to believe that they're living in the coop/run somewhere, but I can't figure out where.


To try to answer some of the questions:

All of my windows and vents have the same 1/2" x 1/2" hardware cloth on the inside of them, so even if they could get to the windows or vents, I don't see how they could get inside that way.

I have been baiting my snap traps with peanut butter. Unfortunately, it has been so cold here for the last few days that the peanut butter is rock-hard, but I hadn't been catching anything with it before, either.

I'll try to post some pictures of my coop/run later.

If they are truly getting through my 1/2" x 1/2" hardware cloth, I don't know what I'll do to keep them out. Can't replace it with the 1/4" x 1/4" stuff.