There is a 10% commission on sales. If you sell a wolf for 500 mushrooms, 50 of those mushrooms will be lost. If you sell a wolf for 10 mush, you will lose 1 mush.
Also, I believe this might belong in the bugs forum. :)
This isn't really a bug due to the 10% commission on sales.
If you're saying you got 0 mushrooms from a wolf you sold for 50, please screenshot your secretary bird in the income section of it and post it here. It'd be good if you could link to the wolf that you sold and didn't get mushrooms too
Spring Month: 3 
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