I made a turkey out of modeling chocolate yesterday. He was really cute! This morning, though, he is splotchy. Some parts of him are still dark and some parts of him are light colored. What happened? Can I fix it? Maybe I should have just made him out of fondant.

Possibly...sounds like the fat may have/had started to separate.
Did you use craft store chips or bagged choc chips? If so next time use at least bakers chocolate. The chips are cheap and do not have much (if any) cocoa butter in them.
Not knowing what he looks like (as far as detail)...can you cover him in fondant?

I used bakers chocolate and corn syrup per a recipe that I found on here.

I don't think it would be worth it to cover him in fondant. He didn't take that long to make. I just have already put some details on him. Does anyone have any ideas for fixing the mottled look on my turkey? Could I paint him with melted chocolate?

painting him with melted choc should be fine as long as your turkey isnt extremely greasy or "sweating."