Skinning the hide off an animal is the av melachah of mafshit and is forbidden on Shabbat.1 Rams’ hides and the hides of the tachash2 were used as covers for the Mishkan, procured after the animals had been properly slaughtered.

One may not remove the skin of raw chicken or fish on Shabbat, as this would violate mafshit. The skin of cooked chicken, however, may be removed. This is because cooking loosens the skin and it is already somewhat removed by the time one comes to eat it. Also, once the animal has been cooked it is no longer regarded as an animal but as a food, and the melachah of mafshit does not apply to foods.3