There is a problem with the game I adapted that I can't fix

Hello everyone, I am a student from Taiwan. There is an assignment in the class. I want to rewrite the game I saw before, but I have encountered difficulties.

I want to make the background color change after accumulating a certain score, but I don’t know how to edit it. And now there is also a BUG, ​​why the hen will disappear after laying eggs.

Please come to a master to guide me, please!!!

Your problem was that it was checking if score = 100. But you did not take into account it going over 100 without it hitting 100.

Here is the fixed game: