Well, I can suggest to wear gloves, and then to immediately go in and change all your clothes after handling them, being very careful not to touch your face or something. When I was a kid I would go ride a horse, and she often had poison ivy on her. I was not allergic but my brother and sister sure were... they would blow up like the Michelin Tire Man. So yes, the oils can stay for a long time, and yes, you should be very careful. I doubt that bathing them would work... it's hard to get that oil off. You could check on special soaps for it, there might be some, that are not so strong they would harm the chickens.
It's also possible that only some of them have that oil on them but again be very careful!