Using bait stations to apply toxic baits for rodents is a good way to reduce the risks to non-target animals. Bait stations also protect the bait from undue exposure to damaging weather.
But if you are in an area where use of PVC pipe toxic bait stations is appropriate, then be sure to add a small barrier at the end of each of the pipes to prevent loose-grain bait from flowing out of the ends. Failure to have these end pieces will likely result in some of the loose grain bait being spilled and therefore available to non-targets.
Just be sure that the hole that remains is large enough to allow the target animals in.
Stephen M. Vantassel is a Certified Wildlife Control Operator. He has published several books, including, The Wildlife Damage Inspection Handbook, 3rd ed.