Is this a bad sign?

Hi all! I'm getting my first Maine coon in a week and I'm so excited! My breeder (Gold Rush Maine Coons) said that all the kittens have a cold so he's waiting for them to be 100% healthy before we take them home. Which makes sense, but should I be worried that the kittens are all sick in the first place? I've never bought from a breeder before but this one has good reviews + I've seen good things mentioned about them on this sub so I know they're reputable.

I guess I'm just worried. Is this common with breeders? What questions should I ask them to make sure I'm getting a healthy kitty?