For everyone please review the rules of posting in the P&P section of BYC. Which inclueds not to either glorify the killing of anything or post for effect, and not to protest the killing either.
To the OP you need to be sure the bait is very secure no matter what you use. If they can carry it away they save it, hording is their highest insinct. Those hordes are most often eaten by other critters and you have no control of where they take it. For a free and easy bait station stop by any constructions site and ask the plumbers working for sewer pipe scraps about 1 to 2 feet long, and get some wire scraps from the electrician 3 to 4 feet at most. Put the bait on the wire in the middle, put the wire through the pipe so the bait is in the middle, tie or secure the wire by bending over at each end of the pipe and leave the stations out in areas as needed. I have mine out 24/7 and the chickens can't get the bait, my cats and dogs are safe, and the mouse and rat population is controled.
For mice 4 inch pipe works, for rats better to get the 6 inch and then be sure to go for 2 foot long so the chicken can't reach in for the bait.