It's illegal in many places, including Connecticut, for neighbors to "trespass" with nuisance lights at night. Even out here in the boondocks of the Arizona desert where people are ½ mile apart, it's illegal to leave an outfacing light on all night (I wouldn't want to with mine, either!). They have to be replaced with "good neighbor" lights that face downward and light only their patio, etc., not the neighbor's.
Here's a summary of Connecticut's Light Pollution Definition:
"Light pollution is generally unwanted or harmful outdoor light and can take several forms, including glare and light trespass. Glare is direct light that reduces vision or causes discomfort and light trespass is light that shines beyond where it is intended to shine. The infographic below illustrates how, and in what forms, light pollution occurs."
Anything that doesn't mimic the natural sunrise and sunset upsets the circadian rhythm in chickens, affecting their brain temperatures, health, longevity and egg laying.
Maybe, to keep good neighbor relations, you could ask the neighbors to change to downward lights and maybe (if you really like them and they are resistant) even offer to carry some of the cost?
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I wish we had that sort of thing here. People LOVE those utility pole lights. I figure I moved into the country to get away from streetlights.