How long do iAd apps take to start generating impressions?

Question

I released an app with an iAd in it on Friday. So far it has generated zero impressions with many requests - a fill rate of zero. Most of my requests are in the USA (~90%) s

Answer 1

Yes it is normal and documented.Have you read - https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/iAd_Guide/Introduction/Introduction.html

Answer 2

It takes 1-4 days for an app to start receiving ads. It's normal¹ for the fill rate to be zero or nearly zero for a few days after release.

_{1: This is not documented on Apple's website anywhere, but Apple iAd representatives confirmed this via email.}