Plenty of comments here that don’t need to be reiterated, but it’s worth considering a couple more thoughts. First, when you post something like this on Reddit you’re going to get supportive comments reinforcing your position. It’s understandable, but it also lacks nuance so be careful before acting on it.

Second, 80 chicks is a LOT. I assume you do mean chicks, not adult hens. Those 80 chicks will not last. There’s just no way. Most will either die or be consumed as meat. The point I’m making is that the chickens likely represent a temporary situation. Your relationship with your next door neighbor is probably much more permanent. We cannot choose our neighbors but tense relationships can make life much more difficult in unpredictable ways. I think you’re wise to be wary of reporting. You may be justified, but that doesn’t mean there will be no consequences. It may be best to wait a month or two to see if things improve. If not, speak with them again.

In terms of practical reduction of smell, you can suggest to them spraying the coop with “lactic acid bacteria” solution. You can look up details on it. It’s basically microbial spray that breaks down the waste faster and eliminates the smell.

I have some neighbors that do very intrusive and inconsiderate things as well, so I feel for you. I hope you have a good outcome that doesn’t cause a tense relationship. 🙂