Some Hard-Boiled Shailos

Those who cannot remember the past are doomed to repeat it. It is with this in mind that I bring to your attention an incident that occurred in 2004. Some students from Montreal who had recently learned the halachos of kashrus went to view egg production on a farm. They discovered that White Leghorns are among the most popular commercial strains of layer chickens worldwide. The White Leghorn is the most common source of white eggs. Leghorns are excellent layers of eggs (around 280 per year) with a superior feed-to-egg conversion ratio. Leghorns rarely exhibit broodiness and are thus well suited for uninterrupted egg laying. The Leghorn is a light breed that matures quickly to only 3 or 4 pounds and is not considered a viable meat producer. When we eat chicken meat it is from a different variety of chicken.
It seems that these students noticed that the chickens, which, as expected, had four fingers, were perched with two fingers on one side and two on the other. The Talmud (Chullin 59a) enumerates a number of specific characteristics to distinguish permitted and forbidden birds—the most crucial of which is that a dores, a bird with certain predatory characteristics, is not kosher. One characteristic of a dores is that it perches with two fingers on each side of the perch as opposed to kosher birds that place three fingers on one side of the perch and one on the other side. The Leghorn chicken had the perch of a non-kosher bird! The eggs of a non-kosher bird are non-kosher as well (Chullin 65a).