Is this different in meaning from "Jaki chleba lubisz"? I am trying to understand why "rodzaj" is in the sentence.
the question would be "jaki chleb lubisz".
"rodzaj" clarifies the question( that you mean "kind" of bread and not any adjective) but it is not necessary.
Generally, you can. However, "which kind" suggests that there is a closed set of options. And therefore translates to "który". We try to keep those two options apart.