A proper fenced enclosure, a dog-proofed house or room, puppy daycare, or even a crate are all fine methods of keeping dogs confined while at work. Crating while at work is no different than crating overnight. With all of the options available, there is truly no need for chaining - which is physically and mentally destructive to the dog. I have rehabilitated numerous chained dogs, and the mental and physical damage that needs to be undone is overwhelming - sores and infections from collars and harnesses, embedded collars and chains in the skin, damaged nerves and muscles due to the limited and repetitive movement permitted on a chain and the weight of a chain, the inability to properly interact with other dogs while loose with them, the inability to walk loosely on a leash, food aggression, resource guarding, obsessive licking and gnawing, obsessive barking, and the list goes on and on!!