@Joerg59
Obviously they broke the rules, are obnoxious, and the dig is a danger.
If they are still there, call Airbnb and get a neutral cancellation based on safety issues.
Just a thought, what if it hadn't been a chicken, but a child or grandchild?
Just my opinion. Definitely leave an honest review, mindful of wording so that it can not be pulled by Airbnb.
As an example, we recently had guests who partied, illegal drugs, noise, nudity. The star ratings we entered were appropriate, the key was that the public review was "Cleaning took more time than normal, not a good fit". The guest had Airbnb pull his/her review. My review of the guest remains because of the neutral wording. Savvy hosts will realize that the cleaning issue also suggest broken house rules. Subtle but effective.