The laws of sacrifice as they appear in the Torah itself, particularly in Leviticus, are comprehensive and complicated, though not exhaustive.
There was undoubtedly an extremely detailed priestly tradition on how to deal with each type of sacrifice, both as regards the actual ceremony and the various flaws that might be found in the sacrifice itself.
Sacrifices were rejected when the animal itself was flawed or when the thought or intention was unworthy, thus invalidating the offering.
Even in the talmudic era the laws of sacrifice were regarded as the most involved in the Talmud.
As a certain sage said to one of his disciples:
"Such a difficult problem belongs, from the point of view of gravity, with the laws of sacrifice."
The complexity results not only from the abundance and intricacy of the details but also from the basic intellectual theories underlying this type of law.
Unlike civil law for example, which is essentially rational, laws of sacrifice are based on very ancient traditions and customs for which no apparent explanation exists.
In the talmudic period it was emphasize that, unlike other halakhot, laws of sacrifice should be studied and analyzed with great caution, and methods of study appropriate in other spheres were not always effective in this area.
The scholar cited extensive proof that halakhic methods relevant and applicable elsewhere cannot be employed in deliberations on laws of sacrifice, which constitute a world apart.
At the same time, the scholar who becomes reasonably erudite in this field begins to discern a special kind of logic that can serve as the basis for more profound examination.
–Rabbi Adin Steinsaltz
From The Essential Talmud by Rabbi Adin Steinsaltz