Hello Don, I wonder whether you have field mice? In a way it matters not except that your carrots are gone.. Another year I would harvest them by late October to store in sacks, somewhere cool. Rats could find them and I do put some poison down in my barn in November and then keep it topped up. But rats are clever and sometimes eat the produce first.
Kate, I have no answer really, especially as hens mean food for rodents. If you do use poison, make sure to keep some there all the time until it stops being eaten, so the rats perish before perhaps acquiring immunity.
I think the mild weather has helped rodents to thrive.