I'm not good at this type of games, so I didn't get very far, but so far it's fun :)
Here are some things I'd improve:
1) - Sometimes, it's unclear how far and at what angle I need to be from enemies to pass undetected. One time, I can pass by 3-4 steps in front of their face and I'm good, other times they see me from the other end of the barn. And I wasn't even in the spotlight.
2) - I know it's grid-based, but maybe allow continuous movement? I mean, just let the character walk in the direction you are pressing the buttons. They can move with similar grid-based intervals, but at least keep walking/running.
3) - There is a 1-1.5 sec delay when you open the door. It wouldn't be such an issue, but when a farmer chases you, it could be a real bummer.
4) - For the atmosphere, when you are detected, maybe have the chicken cluck more often and more furiously? Like it's running away.
5) - Maybe some voices for the farmers, like how they want some chicken for dinner. It could add to the tension.
Other than that, really cool. Keep up the good work!
BTW, this game needs a version with a duck :) Or at least a level where your chicken needs to cross the road xD