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Reporting
Although we have heard ofAlthough we have heard of putting leaves in (plastic) bags in the fall to hasten decomposition, we are not familiar with the (any material) bag idea for manure. Leaves do not contain the acidic components that are found in animal manure so it is relatively simple. It would seem as though hot manure alone might "eat" through the bag before too very long. Manure mixed with existing compost and put into a bag might be a little "weaker"...but other conditions are not known (your weather, the moisture level, and perhaps other things). Where did you get this idea? It might be worth your while to ask the source. A final thought would be to compost your existing chicken manure the usual way (in an outdoor pile) this season and acquire manure for this growing season elsewhere. Then next year, you will have a ready and reliable batch. Sorry we can not be of more help with this.