Just Another Rotten Flesh to Leather Mod
With JRFTL you can convert Rotten Flesh to Leather. By Default, leather is created by smelting rotten flesh. However, when the HardMode is enabled in the config file, first a prepared flesh has to be crafted from 4 rotten flesh and then smelted in a furnace.
You are free to use it in any Modpack, just link this site. And it would be nice to send me, or comment, a Link to the Modpack, if it isn't on Curse.