I noticed this when my custom reward from TurkeyUtil quit working. But the reward definition below now generates a dud block that does nothing. I have changed the id to "minecraft:dirt" with the exact same results. So it looks like Item types are not loading for some reason.

Chance Cubes: 1.7.10-1.5.4.154
TurkeyUtil: 2.2.100

I see this is in the log file:

[14:30:40] [Client thread/INFO] [chancecubes]: Loading custom rewards file vanilla_twist.json
[14:30:40] [Client thread/ERROR] [chancecubes]: Failed to load a custom reward for some reason. I will try better next time.
[14:30:40] [Client thread/INFO] [chancecubes]: Loaded custom rewards file vanilla_twist.json

Here is the custom rewards file:

{
    "Kira's Feather":
    {
        "chance": 0,
        "Item":
        [
            {"id":"TurkeyUtil:Kiraeys_Turkey_Feather","Damage":0,"Count":1}
        ]
    }
}

( Updated @fuzzyray's formatting to be a bit more readable. )

This is my bad. I changed some of the json formatting, but I forgot to update the wiki. Refer to the new example here http://pastebin.com/HtPCjCc0

That was the problem, thank you!