U_Stormcrow
Crossing the Road
^^^ this.Like every other animal owner, you are 100% responsible to keep your animals on your own property.
Imagine if you had neighbors letting dogs run loose to kill your chickens? Your chickens are doing the same thing to the neighbors' gardens.
There are many options for building a run -- chainlink dog kennel panels are one of the easiest if you're not particularly hand.
Chickens (or any creature) of property and off leash are generally considered by the law to be "at large". Being "at large" is, first and foremost irresponsible and disrespectful to the property of others. But perhaps more significantly, in many jurisdictions, either the locals, the sheriff, or the animal control folks can "take" at large livestock - and chickens are almost always viewed as livestock. "Take" does not always mean "kill" (anymore), but it frequently still does.
If you can't keep your chickens on your property, don't keep chickens. Simple.
Same with your dogs (if any).
Knowing more about your situation and location, the fine posters here at BYC can likely help with budget appropriate ways to assist you in preventing your chickens from leaving your property.