Tethering or "chaining" is not to be referred to an animal that is being walked on a leash. Tethering refers to the act of trying a dog to a stationary object using a rope or chains and leaving them unattended. 

Tethering is bad for dogs because they are social beings. Dogs require companionship and interaction with humans/other dogs. Long-term tethering can cause psychological damage turning a normally friendly, well-mannered dog into a fearful and aggressive dog. Not only do they lack social requirements but tethered dogs are often found with wounds along their necks, from being rubbed for so long by their collars. Tethered dogs are also more prone to getting into fatal dog attacks as they cannot get away. They are also more prone to strangulation, heat stroke, extreme weather, entanglement, and unfriendly human harassment. 

Tethered dogs also pose a danger to humans. As I mentioned before tethered dogs suffer from psychological trauma causing aggression. Dogs are naturally fight or flight animals and when unable to flee from harm or danger their immediate learned response is to fight. These dogs resort to attacking any perceived harmful human or animal. Tragically, children are often the victims of these attacks. 

I hope that in the future we can ban tethering dogs to not only protect the future children but to also give dogs the homes they deserve.