Is it permissible to sell a live animal whose meat is eaten, such as a chicken, by weight, if this method is common practice?

It is permissible to sell a live animal by weight, whether it is chicken, sheep, or other animals, by kilogram or otherwise. The basic principle in transactions is permissibility unless the Sacred Law prohibits it. The fact that the animal is alive does not prevent its sale by weight, because the intention is to know the object of sale, and this is achieved through weighing. Furthermore, what is inside the animal's belly, such as organs and food, does not affect the permissibility of selling it by weight, because it is secondary.