From comments from this idiot and others, like members of Congress, Black activists, and even the president of the US, I would think that Zimmerman could never have a fair trial.
No change of venue would help.
Zimmerman has justifiable reason to flee the country since he can have no reasonable expectation of a jury not influenced by outside forces.
Zimmerman may not have a reasonable expectation of staying alive until the trial, let alone a receiving a fair trial, because of the death threats.