**Disclaimer: This article will primarily be discussing the side effects of walking a dog with a collar alone, not the side effects of fitting your pup with a collar for identification purposes.
Simply put, attaching a leash to a dog’s collar for a dog walk is almost always harmful. The side effects may not be easily seen at first, which is what I’ll be going over. I hate seeing young puppies toted along in the park with just a collar, and I hope this information can be used to educate those who may not know the risks!
When doing my research for this article, one of the most startling things I discovered was that paw licking is an extremely common warning sign that a pup is starting to experience a negative side effect. When dogs lick their paws, they’re treating a tingly sensation that’s caused from leg nerve damage. If a pup begins this habit, it’s best to look into their current walking fit and check if everything is fitted appropriately if you’re already using a harness.
Another common side effect is neck injuries. While using a collar to walk your dog is dangerous on its own, even more dangerous is leash training with a collar. Young puppies may not understand why they’re suddenly being yanked around, even though it seems obvious how we’d like them to behave on a walk. “Stay close to me, don’t jerk around, and don’t run up to other dogs.” The truth is, when the only feedback a pup receives is leash movement, they don’t understand what to change. Leash training with a collar can lead to severe neck injuries, and whiplash. This is why recurring commands help with training so much more!
Thyroid damage is also a large risk for dogs who use a collar. Human thyroids control so much in the body, and it’s no different for dogs. Most collars rest right where the thyroid is located, so the continuous stress can lead to an array of spooky side effects.
Harnesses allow the force a dog pulls on the leash with to spread apart, allowing for overall less negative side effects. Harnesses also offer customizability, based on a dog’s walking behavior– I highly recommend checking out my Top Three Harnesses post where I go over some of my favorite collar alternatives. (:
Happy walking!
Sources: https://bit.ly/3gMzbea
Pink's Pups 
Always informative. Thanks for the update!
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