Our chicken coop is a small building with an interior floor about eight feet on each side and about a five foot wide double door at the back that allows me entry and makes cleaning out the bedding easier. The chickens enter and exit through two small doors at the opposite side, allowing me to come and go without chickens underfoot. There is a small closet in the back corner in which we keep the feed containers and other small equipment that we sometimes need for the chickens – extra waterers, a water heater for winter, and other miscellaneous things.
Because the building is not only insulated, but also heated by a heat lamp in winter, this building creates a desirable environment for mice. As the fall temperatures drop and mice begin looking for a relatively safe place to overwinter, the chicken coop becomes ever more enticing, and we see the numbers of mice increase. The coop sits within a fenced yard to keep the fox and raccoons out, but that also tends to keep our cats out – allowing the mouse population to grow. It is not unusual to see a mouse scurry off as I open the closet in the back of the coop to feed our chickens. Over the years, I have had to accept this as a fact of farm life – it is almost impossible to get rid of mice in the coop.
Yet, I’ve also noticed something else. The mice in the chicken coop are unusual in that they have no tails. I’ve seen dozens of mice over the past years – maybe hundreds! – some obviously mature adults and others still immature young, but each and every one of those mice was tail-less. And that made me curious! What was going on with our mice? Was this a mutation that just happened to occur in this population and was now breeding true in this isolated colony? Or was there another explanation for the smooth rump and missing tail that marked each of these chicken-coop mice? I’ve been watching and pondering about this for years – and believe it or not, I eventually figured it out (and it didn’t take much!).
Not long ago, I was in the chicken coop with the closet door open, shoveling grain into the chicken feeder when a young mouse ran across the threshhold of the closet door. It so happened that this particular mouse did still have a tail, and I mentally noted that fact, musing that obviously some mice of another population do make their way in among the tail-less. Was the no-tail mutation (if you could call it that) dominant, explaining why the vast majority had no tails, or was there something else going on? In that instant as I puzzled yet again about the unusual anatomy of these mice, one of the several chickens around my feet quickly and efficiently struck forward with her beak and clipped off the mouse’s tail, and with a squeak, the mouse ran off – now tail-less like the many others. As for the tail, that hen gobbled it down like a small worm, quickly surveying the area for more! No wonder we had so many tail-less mice! So much for my thoughts about genetics!
Since that time, I’ve come to realize that chickens are ruthless mousers – almost as good as our cats. Although our chicken coop always has a certain number of resident mice, there are surprisingly few. The population is kept down by the chickens themselves, who are happy to eat any mice they can catch. In fact, they will fight over a caught mouse, chasing each other squawking and shrieking with feathers flying in an elaborate game of keep-away where the winner gets the spoils. The only reason we still have as many mice in the coop as we do is because of that closet at the back; the mice are protected there and, if they are smart enough, they can hide in the closet until the coast is clear of hungry chickens. Those mice that survive do so because they sneak out to grab food or drink water only when the chickens are distracted elsewhere – and they run back to the safety of the closet before they are discovered. It is obviously a dangerous life for a mouse in the coop – and nearly all have given their tails as a badge of bravery in the process!