In reply to ozbaker: Start off slow and steady. depending on the breed you could take them for relatively long days around 8 months on wards though 1 year is better if you don't want them to develop arthiritis etc. I would just work on call back and stay commands in the meantime as it only takes them to chase one sheep for them to end up in trouble (cliffs, farmers, etc).
I would recommend feeding them a high quality working dog feed like CSJ or eukanuba and make sure it's high protein for puppies.
I have a 7 month Collie and he is very adept at scrambling already though I have to be careful he's not taking too many risks as they can be a little fearless!