Yes, teaching a dog to jump is important but I do not think it should be started too early because the exertion can damage a pup’s soft bone structure.
Depending on the dog, I don’t usually move into this area until it’s ten months to one year old.
When jump training gets underway I make it as natural as I can in the early days, getting the pupil to ‘skip’ over low fallen tree trunks and the like.
To help these lessons along I have built a jumping lane in my rabbit pen where I throw a retrieve and encourage the dog to clear the obstacle.
As the dog grows in confidence I slowly increase the height of the jump.