Are all planks listed as valid manmade places to spawn? Or is spawn rate simply too low?

Checked, and the planks are all valid spawning structures. Lifted spawn rate in the hopes it'll improve, but giving Burmy and Phantump more leaves and other materials should also make them more desirable to farm. Rotten Flesh needs to come from a beginning mon. Shedinja? The problem with Shedinja and the Duskull line is both should be dried out and well preserved, not rotting.

Rotten Flesh Drops From:

• Shuppet (wtf is in that puppet sock XD XD XD)
• Zubat
• Noibat
• Trubbish

Rotten Flesh Added To...

• Burmy/Wormadam Trash
• Diglet/Dugrtrio Pink
• Duskull has rare chance
• Venonat
• Drowned Magikarp

None of these corrects for the fact that exactly zero of the Pokemon coming out of the starting spawners give rotten flesh. Leaves will have to do for now.