Fifty chicks arrived in the mail on Wednesday morning. While the Monster seemed amused by the chicks for a while, I'm pretty sure Chacey was more excited about them than he was.
Chacey takes her job as guardian of the chicks very seriously. No cats get near the chick coop while Chacey is loose and she had serious doubts about letting River get near them as well. I'm pretty sure she knew what River was thinking.
I'm also pretty sure she knew what the Monster was thinking.