[Joannav53]

We currently have a problem with rats in our chicken run on the allotment. Are rat proof feeders any good. Any advice on getting rid of the critters

[grinling]

How have you enclosed the chickens?
Recommended is wire which is buried as an L shape at least 1 spade depth and 2 spade width to stop them digging in.
You should see round holes where they are getting in.
Compost bins wired underneath as they are cosy places to nest.
You can use wire cage traps, but these can be triggered by mice, you the have to humane kill afterwards.
You can use large snap traps. Glue the bait onto it, be careful setting them as the springs are heavy. Make sure the chickens cannot get to these as well as wildlife. Propped up overturn bucket helps. Check daily.

[New shoot]

If you are leaving chicken feed out overnight, that will be a big draw for the rats.  Assuming you are not around to take it out of the run each night, a rat-proof feeder would be a good idea, or you can hang up a feeder to get it off the ground and make it a lot more difficult for rodents.

Here are a couple of articles from the main site, which might be useful 

https://www.chickens.allotment-garden.org/keeping-chickens/rats-vermin-around-chickens/

https://www.chickens.allotment-garden.org/predator-protection/pest-control-rats-mice/

https://www.chickens.allotment-garden.org/poultry-feeders-and-drinkers/