This means that he had boiled the ram's shoulder. This can be stated in active form. AT: "the shoulder of the ram that he boiled" (See: [[rc://en/ta/man/translate/figs-activepassive]])
Here "separation" means "dedication." Also, this abstract noun can be expressed with the verb "separated." AT: "indicating dedication" or "indicating that he has dedicated himself to Yahweh" (See: [[rc://en/ta/man/translate/figs-idiom]] and [[rc://en/ta/man/translate/figs-abstractnouns]])