OP, I get where you are coming from. I'm the type that feels better the more I learn about these kinds of situations. I did my own research and feel better. At this point, the information is so conflicting it is hard not to be concerned. The whole thing is really hitting home to west coasters it seems. Knowing that the same scenario could play out here and is a "not if, but when" situation. The coast and towns of Japan look very similar to the Pacific Northwest coast. I think this has served as a wake up call to folks about how fragile infrastructure and disaster response actually is, even in developed and prepared countries like Japan. I know people who are just now thinking of preparedness issues as a result. Evacuation is a real inconvenience and it never hurts to have a plan in place. Sadly, it seems that one true great cost of this fallout is likely to be the marine ecosystems and the rich fisheries east of Japan. And of course, the horrible toll to the island of Japan and the Japanese themselves.
After Chernobyl, measurable radiation effects were noticed as far away as Germany which is about 2000 km from the site. Much closer than we are to Japan and the Chernobyl situation was much worse. Contaminated milk was a real problem around there due to the contaminated grass the cows fed on. The feed you give to your chickens will not be contaminated so the eggs are fine. And I don't think chickens live long enough to have health concerns from it anyway.
At any rate, it never hurts to eat well and take care of yourself and the animals, I would definitely NOT be taking ay extra potassium iodide or other sources of iodine at this point because the radiation levels are still normal. It does stress the thyroid to take 1000x the daily dose. You don't really want to do that unless you have to. I can see folks buying the pills just in case, but now is not the time to take them. I don't have any and I'm not stressed.
Here is a radiation monitoring site of independent station operators for peace of mind.
http://radiationnetwork.com/index.htm
Now, please excuse me while I go finish the tin foil hats I am making for the chickens and cats. I am using heavy duty foil in case anyone was wondering. It is so hard to keep on the silkie's crests.