How do you figure this is a parable? Not being rude but what you said is something you made up. Nowhere does the bible equate dead bodies with unconverted mankind. Nowhere does the bible equate an eagle as a place of unbelief. I mean come on, Jesus is foreshadowed as an eagle in the Old Testament, God bears us up on eagles wings.
Parables are prophecy as a source of faith (no difference) .He spoke in many manners.
Many make parables into nice little stories with no spiritual value as fictional tales (the literalizers )
The Bible informs us that without parables using the things seen to gives us the unseen spiritual understanding, the gospel, he spoke not.
2 Corinthians 4:18 While we look not at the things which are seen, but at the things which are not seen: for the things which are seen are temporal; but the things which are not seen are eternal.
The use of the unclean to represent unbelief is not something to be ignored . search it out. It is used just as Balaam Ass to represent God is not served by human hands as if he who satisfies all nededs neded something from the clay he is forming in .he can use a unbeliever to bring the gospel as well as one that has no faith .
Leviticus 11:1And these are they which ye shall have in abomination among the fowls; they shall not be eaten, they are an abomination: the eagle, and the ossifrage, and the ospray,
Jesus is not foreshadowed as an eagle in the Old Testament, an eagle is typified as a uncelan fowl . Jesus is typified as a lamb in parables. if the Ass is not redeemed with a lamb break its neck .