I’m mostly in this camp too...mostly because of the fact that OP @buffy-the-eggpile-layer says the neighbors are friends. So far, the words mostly fall on deaf ears. A direct or strong approach might sour the relationship. And a bad neighbor relationship is no good.Honestly I'm really not interested in having "tough conversations" that could sour a neighborly relationship. On the other hand the behavior of the chickens would annoy me. Personally I think I'd just go with the path of least resistance and leave feed out near the property line. I wouldn't be splurging on good food either lol. But if you can afford a bag of cheap feed and it keeps the peace between your neighbors and the hens I would go that way. I realize this would not be for everyone. But I just personally wouldn't cause a stink over this.
however, this is bags of feed...granted they can go cheaper on the extra feed. But it would be hard to keep them out of the coop/run when it is open, so they would eat the flock feed anyway. It depends on what OP feels is the real issue and if it’s a livable situation or not. If not, what can change realistically? OP knows them and what is important to them, and what isn’t so difficult for them to hear. Not sure, but an off handed remark about how they rush your feeders every day combined with the fact that fewer bugs and forage are to be had in the past few months might make something click for them.
Eventually these chickens will pass away, the neighbors may not get any more. But they will likely still live next to you, so keeping a good relationship is important.