What is the benefit of pulling out a chicken’s tongue before slaughtering it, and why is this not done for ducks? And is there any particular benefit to holding one leg of a chicken tightly during its slaughter?

The legitimate method for slaughtering chickens, other birds, and edible animals is by cutting the windpipe, the two jugular veins, and the esophagus, with a difference among the imams regarding the required extent of the cut. It is not a condition for the animal to be permissible (halal) to throw the chicken to the ground, hold its leg, or pull out its tongue. Avoid anything that constitutes torture and serves no purpose; for the Prophet, peace and blessings be upon him, said: "Indeed, Allah has prescribed excellence in all things. So when you kill, kill well, and when you slaughter, slaughter well. Let each one of you sharpen his blade and relieve his animal."