Generally speaking, breaking older dogs of acting improperly around chickens is easier than with pups. It is very much faster. Even when older dog has a history of killing chickens it can be done. Coonhounds, dalmations, labs, and border collies are the ones I cut my teeth on without formal training myself. Breed can be important but individual differences can override. When I think older. I assume it is at least 2 years old. It is also assumed the dog is socialized to be around humans and sometimes even around other dogs. First objective is to get control over dog where it ceases to do something when you give command. Get to that point then we can address the particulars of how to proceed. Dogs differ as individuals in ways that are significant to what needs to be done with subsequent steps.
This will be a multi questions, I'll try to stay on topic. I have 4 RIR's, 3Brahamas, 4 Black Beauties (I think), and 5 banties, 10 guieneas I free range from daylight till dark. I got my flock from the local feed store the last week of May. I have no dog but my neighbor has 6 full blood registered German Shepard pups for sale. I'm not sure I'm ready for another dog right now after we had to put our corgi down because of cancer. (My wife treated him better than she did me. Lol that's a whole nother thread). Any experience with GS's being good guard dogs for chickens? I have not lost any to preditors yet. Emphasis on yet. I did here coyotes 2 nights ago so I took my flashlight that flashes red continueiously and put it out by the coop, because I had 6 guineas on top of the coop and 2 on a trailer behind the coop. No losses. At what age should I expect them to start laying so I can keep them on the run till they have laid? I have 2 white Bramha's that have a fairly large comb and 1 that does not. One of the large comb clucks like a hen but looks like a rooster, any thoughts on that. Then of my 4 RIR's 3 are for sure hens and one has a much larger comb, bought all the same time tagged as hens. Your thoughts on that. Thanks Willie