The student experiment at Cal Poly is now officially over to our knowledge. Future experiments are said not to be planned or the lenses to be recommended for commercial use. In January 1992, about 400 of the original 1,000 hens were estimated to remain in the poultry unit waiting to be "phased out," i.e., sent to slaughter. Contacts with school official initiated by UPC and Action for Animals' Rights (AFAR), a group based in Atascadero, CA, have not, in our opinion, resulted in a responsible show of concern for the welfare and suffering of the hens. For example, during the experiment the hens did not receive, nor do they now receive, veterinary care and treatment of their eyes, according to our sources of information.

In July 1991, a concerned citizen removed several of the experimental hens from the poultry unit at Cal Poly. Photographs were taken of the hens in the unit and of those who were removed. The hens were taken to Dr. Nedim C. Buyukmihci, V.M.D., Associate Professor of Ophthalmology in the School of Veterinary Medicine at the University of California, Davis. Dr. Buyukmihci's July 25, 1991 report on his examination of these hens supports his earlier one based on his examination of a pair of lenses. He explains that "The red plastic lenses are at the very least uncomfortable for the chickens. These red plastic lenses also appear to cause corneal ulcers. In the worst case, these ulcers can rupture and lead to blindness. Pain always is a significant component of corneal ulcers or ruptured eyes."

Dr. Buyukmihci also expressed concern over the fact that these non-biodegradable lenses are to be disposed of by being ground up along with the chickens' heads, which means they would be recycled back into farm animal and pet food. This could present serious health, safety, and environmental hazards, particularly in large-scale production.

Background

Problems with the Lenses

Animalens asserts that unlike the human lens which lies directly on the cornea, the chicken lens sits above the nictitating membrane (the chicken's third eyelid which helps keep the eye clean and moist) and that properly inserted, the lens does not touch the cornea. Professor A.T. Leighton Jr. of Virginia Polytechnic Institute, who took part in developing the technology for Animalens, told UPC that as long as the nictitating membrane moves freely beneath the lens, the eye receives sufficient oxygen, stays moist, and does not receive corneal damage.

However, Dr. Buyukmihci observed in his report of January 14, 1992 that this assertion is "much at odds with available information about the functional limitations of the bird's nictitating membrane." He explains:

A major function of this structure is to sweep across the cornea, cleaning it and redistributing the tear film. It is very thin and not vascularized sufficiently to be a primary source of oxygen, so it matters not that it may be below the contact lens. Moreover, its contact with the cornea is only for a fraction of a second several times a minute; at all other times it is tucked away in the corner of the eye nearer the beak. In order for it to be a significant provider of oxygen, it would have to remain in contact with the cornea for a relatively considerable period of time, especially because of its relatively poor blood supply (compared with the alveoli of the lungs, for example). There is little possibility that its brief contact with the cornea could result in any significant oxygenation. A major source of oxygen for the cornea is through the absorption of this gas from the air by tears, something not efficiently possible with the contact lens in place.

Another serious difficulty associated with the use of the lenses is the high ammonia, low oxygen content of the typical commercial poultry environment caused by overcrowding and excremental build-up. In this atmosphere, chickens can develop ammonia burns, a keratoconjunctivitis caused by exposure to ammonia fumes produced from unsanitary conditions. Afflicted birds rub their heads and eyes on their wings and let out cries of pain. They stay quiet in one spot with closed eyelids and stop eating. They go blind. Thus, the indwelling oxygen deficiency of the lens is exacerbated by the oxygen- deficient environment the chickens would be forced to live in.

Animalens' claim that chickens with contact lenses are "calm" shows scientific naivete at best. In chronic pain, discomfort, or distress, chickens and other organisms, including humans, tend to acclimate to the chronic noxious stimulus showing only very subtle outward signs of pain. They reduce their activities, develop guarding behavior, and may even deteriorate to a state of learned helplessness indicating that they have succumbed utterly to helpless despair and the destruction of their personality and will.

Asked to comment upon the use of the lenses in commercial production environments, poultry scientists, including Paul Siegel, Andrew Yersin, Frank Edens, Eldon Kienholz, and Joy Mench, have expressed reservations summarized as follows: 1. The bird could not remove the dust, feathers, or other particles (common in production environments) that could become trapped under the lens; 2. The dusty ammonia-laden atmosphere would probably cause considerable infection; 3. The lens would often be incorrectly fitted by the handler, forced by economic considerations to work fast. Improperly fitted lenses would shift to the side causing even more problems and, in some cases, lenses have been known to be mistakenly placed beneath the nictitating membrane; 4. The nictitating membrane is not enough to relieve the irritation of having a foreign object in the eye for a whole year, or to keep out all the dust; 5. The lens would have to be uniformly smooth or rough edges could catch on the nictitating membrane; 6. Chickens in commercial environments need to develop a stable social structure to reduce tensions and nonadaptive energy expenditure requiring visual recognition and memory; the lenses would effectively discourage this; 7. The real problem is specialized breeding for aggressive birds plus too many birds per cage. The answer is to breed for less aggressive traits and give birds more room in cages, or to put them on the floor with ample room or quit exploiting chickens altogether.

Incredibly, Animalens, Inc. asserts that the lenses can be installed in the naked eyes of chickens "by unskilled labor." When UPC asked 3 Animalens- sponsored researchers and 1 production manager whether the lenses, once installed, were ever removed for treatment or veterinary examination to their knowledge, the answer was uniformly, "No." Robert Spiller, the principal researcher in the student experiment at Cal Poly, even wrote, "Once the lenses have been installed, it is not possible to remove them without damaging the bird's eyes." However, Dr. Buyukmihci states, "This simply is untrue." He writes:

When I first saw the photographs of the lenses in place and examined the lenses, I, too, thought that removal would be problematical. Since then, however, I have had the opportunity to examine personally several hens with the red contact lenses in place. Although I had to be careful, it was relatively easy for me to remove the lenses in every case using various fine eye forceps. As I have relayed to you previously, there had been considerable damage already present in some of the eyes. Removal of the lenses did not further traumatize the eyes.

Conclusion