My dog looks depressed because my parents didn't buy chicken when they went shopping?

every Thursday my parents bring home a BBQ chicken when they go shopping, this week my parents decided not to buy one and my dog looks very depressed, even my parents noticed. my mom said she's going to buy one next week. my dog is laying on the floor looking grumpy. My dog goes nuts over chicken and she seems to know the shopping day because she gets excited in the morning..