What is the ruling on eating chicken that consumes carrion of its own kind? Is there a specific prohibition on eating such chicken, or does the prohibition extend to all chicken if this phenomenon is widespread among them?

A carcass is impure. If a chicken eats a carcass and the taste, color, or smell of its meat changes, it becomes a jallalah, and it is disliked to eat its meat until it is fed for a sufficient period to remove the change. However, if the consumption of impurity was temporary and did not affect its meat, it is not considered a jallalah, and it is not disliked to eat it. The Prophet, peace and blessings be upon him, forbade eating the meat of a jallalah or drinking its milk until it has been fed for forty nights.