So far you are the first person to encounter this bug. We appreciate your feedback and we will look into it, the game is still in development so every comment helps.
If you reinstall the game do you have the same issues?
The first time I played from the zip, downloaded and unzipped. Since you asked, I re-unzipped, same thing happened. Then I downloaded the exe and played from it, same thing again. Every time the tower "bocs" a new chicken appears but doesn't launch until I have this strange looking stream of chickens inside the tower. One other odd thing about it is that the tower continues to aim at the same first zombie no matter how far away it gets so maybe something is off about how the range is being executed.