чтобы собака могла бегать по проволоке

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A drag leash is a light weight leash that is designed to be used by trainers who want to let their dog drag a leash so they can quickly grab the line to either control the dog or to give a correction. A drag line should not have a loop handle. When dogs drag a leash with a looped handle their hind legs are constantly getting tangled in the loop. This can cause a bad injury if the dog is running and it trips them. I have heard of dogs actually breaking a rear leg when this happened while they were running.