I found this really interesting link to a PDF file while surfing the interwebz that I want to direct you to regarding the “hole” as it relates to our roller pigeons. While I can appreciate the thought and effort applied to this topic by its authors, I think describing it, as a rabbit hole would be a more apt description (tongue in cheek).

I have personally seen more evidence of style of roll ( H  (-)  X  >< ) than of any real proof of this ever elusive hole. To pursue something in which the likelihood of ever actually seeing with ones own eyes is to go down a rabbit hole and never come out except with complete exhaustion knowing that you will rarely if ever actually see a hole.

To avoid the rabbit hole simply measure what you CAN see - and that would be style of roll. Simply stand under your birds and learn to recognize style ( H  (-)  X  >< ), this will reveal far more about the quality and value of a birds performing qualities and your breeding choices than trying to strain to see an elusive hole.

Learning the mechanics of the roll is important and will influence our judgment toward a bird as to its value in the breeding loft.

LINK: HOLE NO HOLE