Which menu item includes both shrimp and chicken?

The item that includes both shrimp and chicken is indeed the one known as "Chicken and Shrimp on the Barbie." This dish combines the flavors of grilled chicken with succulent shrimp, prepared over an open flame to enhance the overall taste. It's an iconic offering at Outback Steakhouse, showcasing their expertise in combining different proteins grilled to perfection with their signature seasonings.

In the context of the other options, "Surf and Turf" typically refers to a combination of meat, often steak, with seafood but does not specifically denote shrimp and chicken. "Chicken on the Barbie" is solely focused on chicken prepared with the same grilling method. Meanwhile, "Steak and Shrimp Combo" pairs steak with shrimp but does not include chicken. Thus, the correct answer is clearly distinguished by its inclusion of both chicken and shrimp.