Why the rooster? According to Scribal Terror:
Iconographically correct, if that's supposed to be a rooster. From the earliest days, Christians have viewed the rooster as a symbol of the call of Christ, signaling a new dawn for humanity. If you Google "rooster as Christian symbol," however, you will find a number of alternatives to this interpretation, both positive and negative. That is typical of the medieval world view, which saw all things as symbols with multiple meanings that could be viewed "in bono" or "in malo" (for good or for evil).