That feeder is pretty interesting...never seen one before.I switched to one of these feeders and that really helped. https://smile.amazon.com/gp/product/B01LM6TRRC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
I also put a dog crate inside the coop that had active rat traps in it, so that my dogs/chickens could not access them but any rats/mice going into the coop could. We had no rodent problems for years, until a vacant house close by went under construction, and between the new feeder and the traps we've really gotten things back under control. Good luck.
Tho not sure I buy it's totally chicken spill proof,
but can't tell how deep the feed is in reservoir.
Is it easy to take part to clean?
How big is the opening for chicken heads?
Snap traps in wire crate is a good idea too...how much success did you have with it?