anywhere between 4-6months is fine really, my hv doesnt like blw and didnt have a good word to say about it and there has been babies losing weight through it, which i dunno is true or not as people have had fantastic results on here.
i started rhys at 4 months, his hand and eye co-ordination is great, he swallows and chews properly, he eats in between bottles so is not replacing food with milk, he holds his head perfect, will sit and suck on rusks so there's no way he'd have waited till 6 months,
you'll know when he's ready dont be pressured into doing it before 4 months or having to wait till 6 months, if he's not ready its very hard to force feed a baby thats what my hv told me.
xx