WHy the heck does chicken got wings, but can not fly?

The wild ancestor of domestic chickens is the red jungle fowl, which is a bird that can fly and still lives in the wild in Asia. Many birds (e.g. ostrich, kiwi, cassowary, dodo) have evolved flightlessness from flying ancestors, because they live in places, such as islands, that do not have ground predators. Their wings were therefore a useless luxury. Since flight muscles require a lot of energy to maintain, a bird that loses the ability to fly and its flight muscles in such an environment will have an advantage over other birds, since they don't have to eat as much to stay alive.

Nevertheless, no flightless bird has ever evolved to be wingless, even though they cannot fly. It may be because flightless birds evolved flightlessness by the process of neoteny, meaning the retention of juvenile features in the adults. Since young birds have small wings, flightless birds too have small wings, since they are overgrown or big chicks. Since their wings are tiny, there is really no advantage to losing the wings altogether, since there isn't much muscles in the wings. Indeed, the chicken wing does not have as much meat as the legs and thighs of the chicken. Another reason flightless birds do not lose their wings is because of serial homology. Serial homology is a well known phenomenon in tetrapods (reptiles, amphibians, birds and mammals). Basically the development of the front and hindlimbs are governed by similar genes, so that if something changes to the front limb, the rear limbs are also likely to change and vice versa. For example, pandas have an enlarged wrist bone on their hands that they use as their "thumb." There is a similar bone in their hindlimb, and it is also enlarged, although not to the same extent as their wrist bone. The reason is that the gene that enlarges the wrist bone also slightly enlarges the same bone in the foot.

Because of serial homology, if a bird loses its wings through mutation, then the feet are likely to be affected negatively as well. Since flightless birds rely on their feet to get around, since they can no longer fly, they simply cannot have mutations that can cause them to lose their wings because the same mutations may reduce their legs or even make them lose their legs. BTW, chickens can still fly, although not as well as their wild ancestor the red jungle fowl, because over the years, chicken owners tend to select breeding stocks using chickens that cannot fly very well so as to minimize the number that decide to escape by flying away. Selective breeding has resulted in the chicken's reduced capacity to fly, but it has not resulted in the complete loss of the wings. Not even natural selection has resulted in birds that are wingless. IOW no flightless birds has ever evolved to be wingless, so we should not expect chickens to have no wings.

Chickens can fly.

Sez who? Some chickens fly pretty well. Leghorns, Delawares and RI reds come to mind.

chickens can fly, usually people either clip their wing feathers so they cant, or they raise them away from adults so they never learn to fly. If they don't have adult chickens who can fly to teach them to fly they never will

Chicken got wings because it's a bird. There are other birds that can't fly, like turkeys, ostriches, kiwis and penguins.

They can though

https://www.youtube.com/watch?v=03BO8WCwWas

they are too heavy