In California (Penal Code 597f), it is illegal to tether, fasten, chain, tie or restrain a dog to a stationary object, such as a dog house, tree or fence, unless the dog’s guardian is nearby and is performing a temporary task.  Dogs on a running line, pulley or trolley system can not be attached to it with a choke or pinch collar. 

The dog shown below is typical of many of the dogs we find chained in Oakland.  This dog is very skinny and weighs approximately 35 pounds but had been chained with a huge truck chain that weighed nearly 10 lbs.