As a little girl, I used to always be around chickens whenever I would visit my grandparents. My grandfather grew them and took care of them as a hobby, his entire backyard was full of chicken coops and even had a chicken shed. Because back home we live in a tropical island, there were also lots of trees in the backyard. In my childish deductions and observations, something struck me as particularly odd: the fact that chickens preferred to walk around the ground instead of flying and perching themselves on the trees. Well, I reasoned, chickens are the most useless birds ever, then. However, as I grew up and took interest in other things, I completely forgot about my chicken dilemma and accepted it as a fact that chickens cannot fly.
This is not true, chickens can actually fly! Just not very high up like normal birds can. It is not like there is a select gene that is responsible for a chicken’s inability to properly fly. Moreover, it turns out that domesticated chickens are not actually natural, and they are the result of selective breeding and the hybridization of a red junglefowl and a gray junglefowl, whose existences date back almost 4,000 years ago. Although junglefowls are a little bit more skilled in flying than chickens, they are better adapted to living on the ground; their wings are smaller, their beaks are made for pecking, and their feet are not necessarily made for perching on trees. Because of this, chickens inherited the physical structure of a junglefowl, give and take a few alterations.
Humans protect and breed chickens, therefore, the evolutionary line did not call for them to evolve into animals with bigger, stronger wings. Nor did it call for the elongation of their feet for perching purposes. So, in reality, domesticated chickens do not necessarily need to fly at high altitudes because they can scour for their food on the ground and generally do not need to protect themselves from predators (1). Furthermore, the disproportionality between their body and their wing size makes it incapable for their wings to support their body weight for a long amount of time. As mentioned before, chickens are also the result of selective breeding. Because of select breeding, chickens have bigger pectoral muscles than junglefowls, decreasing the chances of being able to fly at high altitudes for extended periods of time even more.
Human interference has literally created chickens and, ultimately, assigned their role as a means of providing food. Mainly, chickens are bred for laying eggs and consumption. This process has adverse negative side effects, including chickens losing the ability to walk and becoming lame, restriction on food intake, and brittle bones. These factors contribute to a chicken’s inability to fly, as well as intentionally forcing them to evolve less like birds and more like inanimate pieces of meat. This selective breeding and lack of evolution for survival, as well as their predecessors, are the reasons as to why chickens cannot fly.
(1) However, in the case that they would need to, their wing structure would allow them to fly a short distance, far enough to reach safety in a tree’s lower branches.