I don't know how big your backyard is, but have you tried putting her on a lead? We have one for Phoebe that is 25 ft long, so she has room to run in circles and jump around. Our yard is fenced in, but we have a pool, train tracks, compost heep and exposed A/C unit that could all attract a curious little pup. My little diva seems content to lay there chewing on sticks and sunbathing though. 
