I've tried several different ones through the years in our seed house and the only one I've found to work consistently was BootHill.  I use the place packs and tear them open when I place them.  They'll eat it and die.  You might have to put up with the dead mice smell until the dead ones dry out if you can't find them, but it does work.  We are also selling bagged feed out of this same warehouse and if I don't forget to keep the poison out, it will keep the mice/rats out.

http://hogslat.com/boot-hill-mini-pellet-place-packs