I use a special hopper that allows me to run anywhere from 1-3 scoops of food per aquarium and a water line with valve on it for my project and grow out tanks. Here's some pictures:




Basically just take some hardware cloth and some baling wire (or any thin gauge steel wire), roll the 1/2" (for rats) hardware cloth into a tube, then use the wire to "tie" it together in a couple points, cut a bottom piece (I use the portion I cut from the screen lid), tie it on then add a water valve. It also helps to use some wire to hold the water line in the center of the tube so the rats can't chew on it. I run 4 30 gallon long aquariums and 6 10 gallon tanks like this and never had much issue.

Same thing can be done with 1/4" hardware cloth for mice, works much better than letting them throw food everywhere or having to fill water bottles.

Pictures show an old setup I had, I have since closed up the larger holes with more "ties". I'll post a DIY step by step method to this next time I have to make more.