The reason fill rates are typically either 33% or 50% is due the additional ad requests being made for zones that implement picture ads. Video ad request have a high fill rate for most countries. However, fill for picture ads have been extremely limited for English speaking counties, and in most cases not available to non-English speaking countries. A fill rate of 33% is common for new game profiles that still have picture zones enabled. The 50% fill rate typically indicates that the pictureZone is disabled, but that the option to show picture ads when no videos are available is still enabled for the defaultVideoAndPictureZone. Each of these zones will increment the adrequest figure by 1. Video ads on the other hand only make a single adrequest, regardless of the number of zones that use them. With priorities focused making our video ads service the best it can be, we are in the process of temporarily removing support for picture ads from Unity Ads, which is why new game IDs no longer include the "pictureZone" ID. Picture ads have been in beta for some time now. We felt that it would be best to shelve the picture ads feature for the time being, until a later time when we can return to it and finalize the feature.