Hi meetthebubus.
You're very observant re: the eye colour! I had a look on the net and found some info. on the following site:
http://ucanr.edu/sites/poultry/files/186896.pdf
In a nutshell, it says it's to do with whether or not a hen is laying. The yellow pigment from certain foods she eats is put into the eggs when she is laying, whereas when she stops, it is used in her body instead.
In part, it says, "Laying hens will lose their yellow pigmentation in the following order as egg production progresses: ● Vent (orifice from which eggs are deposited) . . .fades soon after egg production begins. ● Eye ring (inner edges of eyelids) . . .loses pigment a little slower than vent. ● Beak (starts fading at base first) . . .totally faded beak indicates approximately 4 to 6 weeks into production. ● Bottom of feet . . . fades sometime between about 8 to 12 weeks into production. ● Shanks . . . a totally depigmented shank is usually a sign that the hen has been in sustained egg production for at least 15 to 20 weeks. ● Hocks and upper side of toes . . . these areas are the last to lose yellow pigmentation. Approximate time in lay can be estimated by observing the successive loss of pigment in body parts. For example, a hen with an entirely bleached beak but pigment still on the feet and legs will have been in egg production for about 4 to 6 weeks. After the hen has ceased laying, pigment will reappear in the same order (i.e., vent first, then eye ring, base of beak, etc.)."
It says it doesn't apply to orpingtons and a couple of others because the skin colour is white, but I think that's why you see it in the eyes. In other breeds, it can be seen in the other areas as well.
The article is very interesting. Worth a read!
