What is this tripe? A Pigeon? Seriously?
Okay. first off. if it is a spy, SO WHAT? it's not going anywhere, especially if you cook it up.
Second, it's a pigeon. PIGEON. BIRD. YES, they can be trained to act as messengers, and the saying dont shoot the messenger playfully toys around my mind, but SERIOUSLY, a pigeon.
IF it's a spy, it's mision can not be fulfilled at this point.
HOW it could be useful as a spy, however, is so far beyond me without an inside operative to check in on the bird, but what information it could provide for anyone is much further beyond me than that.
The more likely scenario is biological sneak attack, not subterfuge.