After finally being able to make an Agricraft Farming Station I have noticed that the Hoe that I have placed inside the F.S is not destroyed once it reaches 0 durability left. I have tried this with both a Diamond and a Wood Hoe. I'm currently using the latest version available to date (0.9.9). Interestingly enough, if you try to use the hoe outside the F.Station it is destroyed instantly regardless of the durability it shows.
Edit: Also, the F.S. keeps using the "destroyed" hoe as if it was a whole hoe.