changing puppy food, how soon?

Hi guys,
We get our new puppy in 4 weeks, the breeder will have her on Iams puppy which we will be changing. The question is, do we start the changeover as soon as we get her, or wait til she is a little older?
Any help is appreciated!
Lynn of Lynn&Pete x

I'd start straight away, just do it really slowly, with her being so young, over a couple of weeks xx

Thanks for the quick reply! Yeah, was planning the gradual thing, we are well practiced, our boy was a fussy eater, and would go off food after a few months!!!

Gradually is definately the best way to go