I don't like using poison because it can take out unintended victims. Last year, when rats were tunneling between two of my coops. I reluctantly invested $40 in a battery operated "electronic" trap that lured the rats in and quickly electrocuted them.
I also installed hardware cloth under both of those coops, eliminated hiding places outside the coops. began ground feeding far, far away from the coops, didn't leave any food in the coops or runs at night and made sure the lids on the garbage cans that hold feed were securely fastened down.
Good luck with your battle! And, my rats were MUCH larger than the mice who occasionally visit my coops -- where my girls like to EAT them! To be honest, I feel badly about having to kill rats, which I know are very smart animals. But they need to be smart enough to stay away from my babies!!!!
I also installed hardware cloth under both of those coops, eliminated hiding places outside the coops. began ground feeding far, far away from the coops, didn't leave any food in the coops or runs at night and made sure the lids on the garbage cans that hold feed were securely fastened down.
Good luck with your battle! And, my rats were MUCH larger than the mice who occasionally visit my coops -- where my girls like to EAT them! To be honest, I feel badly about having to kill rats, which I know are very smart animals. But they need to be smart enough to stay away from my babies!!!!