So I posted the link previously as I thought it had some good replies, but wanted to add:
There are some sprays that will drop a wasp in mid flight, there contain strong nerve agents and are typically oily. Spray a mouse with this and it will convulse violently almost right away. Keep these away from your chickens.
There are other sprays that are intende to be sprayed on the nest after dark, they work differently, and if sprayed onto a wasp it will just fly away. Not sure if this typ is safe around chickens, but I would likobe safer than the other.
I would use one of the safer suggestions at the link I provided in the previous post if it were my chickens.
Sorry for typos, using phone to reply