Hya, Ive had the same trouble with my lurcher, shes 22 inches to the shoulder and very timid. I started her on a short piece of 4" sheep fencing inbetween 2 posts hammered into the ground with small hooks at 4 inch centres on each side. Bent the sheep netting in half to make half the height and hung it on the lowest setting (bout 18 inches) from the ground, Then with the lead on i stepped over first and encouraged her over(a small hop) When she eventually jumped over she was rewarded with food or a throwing of her ball.This way she associates the jump/fence with a posotive. Never drag your dog