Musnad Ahmad Hadith 3003

A sheep belonging to Sawdah bint Zam'ah died and she said: O Messenger of Allah, So and so - meaning the sheep - has died. He said: "Why don't you take its skin?” She said: Can we take the skin of a sheep that died (of natural causes, without being slaughtered properly)? The Messenger of Allah (ﷺ) said to her: “Allah, may He be glorified and exalted, only said: "Say (O Muhammad (ﷺ): "I find not in that which has been revealed to me anything forbidden to be eaten by one who wishes to eat it, unless it be Maitah (a dead animal) or blood poured forth (by slaughtering or the like), or the flesh of swine (pork) [al-An'am 6:145], and you are not going to eat it; if you tan it, then you can make use of it." So she sent for it, then she skinned it and tanned it, and made a waterskin from it that she kept until it wore out.