On my principal job site, we have two buildings that require the presence of mousers. As regular readers of mine would know, we recently lost Moses, one of our mousers, to cancer at the age of fifteen. Our two other mousers are siblings Fred and Ginger, who are about four years old. Fred and Ginger were the offspring of a feral cat cared for by a former site director, who took them in and found a job for them handling mousing duties when their predecessor, Mischief, succumbed to a kidney ailment. Fred and Ginger were not kittens when they arrived- they were lanky adolescents. At the beginning of last year, I was actually concerned about Fred, who was looking a bit gaunt, but this proved to be a dramatic growth spurt, and now Fred is about twice the size of his sister.
Since losing Moses, we've had to figure out a solution to our mousing needs until we can get another cat- nobody wants to split up the Fred and Ginger "team" by having them work in separate buildings. Cats being territorial animals, Moses was very jealous of his turf, even though the incorrigible Ginger tried on numerous occasions to impinge on Moses' domain. Sad to say, Moses and Ginger would occasionally squabble, and Ginger would hide atop a radiator above the communal cat water bowl in a "neutral" building and take a swat at Moses when he came to drink... incorrigible.
We hit on a solution of acclimating Fred and Ginger to Moses' former bailiwick, in effect to brevet them to the new position. Ginger overcame a reluctance borne out of shooings out fairly quickly, but Fred needed to be coaxed into the building. When they are both acclimated to the new mousing environment, we'll probably have them alternate between the two buildings. Fred and Ginger both follow me all over the grounds, so it'll be a matter of playing doorman for cats so we have full coverage.