A nice heist adventure! I love when adventures can avoid combat and this one has a great reason to do it: owls are notable predators to mice! But the hook is also great: duck eggs being stolen and experimented upon!
I think that the best thing about the adventure is that you can pick the random encounters by hand so that you can increase or decrease the tension as you want as they approach the tower, even if the awareness tracker doesn't change.
There's one thing I'd change. Having the passcode hidden in corners around the map isn't explained, feels a bit videogamey. I would maybe paint it on the floor so it's readable from the tower as a "secret in plain view" password reminder. That way mice don't know if a 1 is just a line, or that other sign is a 7 or an L, a 6 or a 9, etc.
All in all a great adventure packed excellently in a trifold pamphlet.