I want to make a stockpile for only rotting items. Is it possible to do this? I already have a refuse pile, but the only options I see is Rotten Raw Hide. What if I have rotten meat or rotten prepared meals? How do I make my refuse pile take only the rotting items
What you are looking for is known as a refuse pile. Any rotting material, including rotten food will be moved by your dwarves to this pile. If you go into the stockpile settings you can exclude other refuse items such as bones or rotten hide. Be aware that items such as clothing or armor placed on this pile will wear(out) at an accelerated rate.
A refuse pile is not the same thing as a garbage dump. A garbage dump is a activity zone rather than a stockpile and will accept only items with the "dumped" flag on them. Any object can be designated as garbage, while your dwarves will only put specific types of items like bone or rotting items on a refuse pile.
In the refuse pile, keep all (or most) of the "Items" turned on, and turn off the bones, hair, rodents remains, shells, and what-not. Regular items (from the 'refuse' stockpile menu) will only be taken to the refuse pile if they are rotten or otherwise extremely damaged. (Rotten food is an "Item" in this instance.)