Poor, bloody thing, the owner has reduced it to that, probably driven it mad ! I wouldn't let up with the RSPCA, I've found from experience that sometimes you just have to keep on at them. I would threaten them with going to the press if they don't act on this poor dog's treatment, that usually works ! Also, if it has no shelter, they have a duty to act as that is a requirement in law nowadays. I wish it lived near me.