SOLVED How to sacrifice animals to perform rite with Celtic augur?

I'm new to the game and can't seem to figure out how to perform rites with the Celtic augur. When I click on the augur, the four rites are all grayed out around his center portrait, and clicking on them does nothing. I've tried placing the augur next to sheep, sacred deer, and regular deer, but the rites still remain gray and won't work when clicking on them. Any help is much appreciated.

 

Hah... I'm only level 5, is that why?

 

Thanks. I was doing a skirmish battle with a friend and assumed I would have access to everything since I was able to get to the gold age and build all the units.