In 28 years having my nice pole building (toy barn) we've only had those cute gray little mice once and I felt so sorry for them having to constantly hunt for food, so I fed them personally and very well. "D-Con" All I can figure is they must have gotten tired of the same constant taste and wanted more variety because they never came back. Maybe if D-Con were too come in different flavors would help their boredom? Picky little fellas aren't they? Probably told all their friends and relation too because even they are boycotting my free food!
Ohhh! how we miss them and all the little tiny babies they used to have! We'd have been very happy to share some of the cute little babies with any of you if you wanted some so you can feed and watch them grow and each have more families so you could enjoy a thriving community right in your own yard! Those "in the house sealed ant farms" are way too small when you can have a "mouse farm" as big as your whole property...
PS: They like to RV too and they don't take up much room or add much weight so why not?