In reply to mypyrex:
My wife has ME (Chronic Fatigue) but usually walks our little cavalier on the beach 4 days a week.
I work away and walk the dog Friday evening, Sat and Sunday.
There is a woman down the road, who has athritis and I've offered to take her dog at the weekends if ever she can't do it, but I imagine that there are lots of people in our area who would be happy to pay for such a service.
The way to make decent money must be ecconomies of scale? If you actually managed to employ 'staff' at minimum wage, walking 4 dogs each per hour, at £10 an Hour, you could be making £25 per member of staff per hour. I guess that you'd be limited to say 10 til 3 as you need to be taking them in the middle of the day.
I also imagine that offering a grooming service on the side would add extra hours to the business. (they charge £££££'s where I live for a simple twice a year 'shave') (we give ours a number 3 all over)
As an aside, my sister who lives in Ohio, takes her dog to "doggie day care" if she's going out for the day and won't be back til late.