The following represents my interpretation of some of Jack Barkel's ideas expressed in the video released in 2000:
In order to deserve a place in the stock loft, the bird's eye must show the following:
5 perfect circles
the circle of adaptation and perimeter need to be of the same color and width
the pupil must be reactive to the intensity of light and must be small
Racing birds do not need all 5 circles!
small and reactive to changes in light intensity
as the pupil or the circle of correlation become larger the perimeter becomes narrower
looking at the sphincter muscle on the periphery of the pupil with a loupe does not allow one to judge its structure accurately and is therefore a waste of time
The circle of adaptation:
clear throughout in pure stock birds
the racing sign is the superimposed black segment
The circle of correlation:
from the pupil to the perimeter
the circle of adaptation and the iris are superimposed on it
if the visible (from the circle of adaptation to the iris) circle of correlation is too wide, the bird would be suited for the shorter distances only
breeding winners with winners with yellow eyes will result in a very thick iris
breeding pearl with pearl will result in a very thin iris with gaps in it - not suitable for long and tough races
Some thoughts on breeding:
never pair 2 pearl eyes because speed and vitality are increased at the expense of the homing ability
pairing 2 yellows will create slow plodders because stamina and homing ability are increased at the expense of vitality
pairing yellow with pearl can result in much speed, stamina, homing ability and vitality
pairing a 100% pearl racing sign with a 100% yellow racing sign will result in pure racers, not suitable for stock.
better than breeding pure racers is breeding the dual purpose bird who can be retired to the stock loft once his racing career is over. To do this, one needs to pair birds together the sum of whose racing signs do not exceed 100%.
PostScript: Jack Barkel had been annoyed by some eye sign cynics and therefore put out a challenge in 1989
Anyone with a champion bird (2 federation wins plus breeding some winning birds) was to put his champion into a basket with 9 average birds. If Jack could pick out the champion, he'd either get it or the appraised value. Should he fail he'd have to pay the appraised value to the owner.
Jack ended up with a lot of money and a lot of champion racing pigeons but has yet to lose in that game. He laments the fact that word about his exploits got around so that the line of challengers has dried up.