You don't always say "estar calvo". If you use attributes like "calvo", "gordo", "flaco", "viejo", etc., the choice between "ser" or "estar" depend on what you mean. If you say "Juan es calvo", you're describing Juan as having a characteristic all bald people do, and include him in such group. If you say "Juan está calvo", you're talking about Juan as having endured a process in which he lost his hair (implying you know he hasn't been bald all his life).
To be dead is the result of an action or a process (a murder, an accident, an illness...).
Same case for:
·El policía está herido; el ladrón le disparó.
The policeman is wounded; the thief shot him. -> His current situation is given by the fact he's been shot
·El canario está lastimado de una pata
The canary has an injured leg. -> Something happened to the canary that brought him to this situation
·Mi muñeca está rota. Alguien jugó con ella.
My doll is broken; someone has been playing with it. -> Transformation was caused by careless manipulation.
And I'll quote myself in
this same thread: