I am trying to develop a well-composted bark material that I can use with plants that like a structured, well-drained, barky soil. This would include plants like Pomegranates (which I have seen do well in a pure bark soil) and Loropetalum (Monrovia grows and ships these in a very composted soil filled with large pieces of composted bark).

A local vendor Lyngso sells a nice bark soil named Rhododendron Mix, with different sizes of bark and mixed with composted turkey manure. If I wanted to further compost that material, what would be the best way to do that? Should I just let that material sit for months in a large container? Should I add some more turkey manure on top and let it help break down the bark? Should I add any moisture?

I don't want to spend a ton of time mixing the material up and would like to find a method that can work over time by just leaving the material in a bin.