Credit To derick15
This you need:
Charles Proxy
Step 1:
Open Charles and Open Farmville,Now make sure that position 0,0 is avaible
(position o,o is just the bottom left corner of your farm) it most be free.
Step 2:
place a haybale in that position and turn on BP in Charles
Step 3:
having BP on move the haybale and place it on the same positon to obtain the Param Info Itemname,Id,Position etc. and take note of it because you will need it. execute twice.
Step 4:
Still having BP on select the Item you want to duplicate and store it, now Charles will pop up and you going to Edit the Param with the Information of the Haybale and execute twice, Refresh the farm and you will have the duplicate item store in your barn.