DD is 10 months in a week or so and is something of a porker (over 11 kg). Consequently, I'm not too surprised that she has yet to crawl/stand/walk like some of her leaner friends.
But nontheless, should I be doing anything to help her develop in this way? She does lots of stretching from a sitting positon but hasn't quite managed to pull her remaining leg away to crawl. She isn't anywhere close to standing up (doesn't really tolerate being held up standing for long, and my back hardly tolerates holding her either )