A dog trained from a pup can be trained to eat from its bowl only. My dogs will not eat anything of the ground, if I'm present or not. Bowl only. As for as chickens go I've kept a small flock 8 or so never a problem with disease or flies they free range. Just fresh water they mostly fend for themselves.Eating out of bowls will work when you are there to watch them.
Middle of the night and a big chunk of bologna or hamburger is a different thing.
Other issue is if you have more than one dog the first one to discover the poisonous treat will gobble it down so the other one does not get it.
The nature of the beast.
I wish there was a sure fire way to stop the poisoning of dogs but Dominicans" in general" do not value dogs.
If your dogs are poisoned here its because of excessive barking, killing neighbors chickens, cats, or you are targeted for burglary.