On my dwarf citizens, I can check their kill list by selecting them with v, opening their status screen with z, and pressing k. Is there any way to view this screen for pets? I have a turret which has earned quite a name for itself, and I'd like to see what it has killed.
As soon as the pet gains a name, it becomes a historical figure. This means it does show up in the "Legends" mode, and you can copy your save game folder, load it, abandon the fort then start a game in "Legends" mode with this folder to check.
You probably want to write down the name of the pet in question, since you can only search by name, not by race.
In fortress mode, you need an extended tool like DFHack, which allows you to write Lua scripts interfacing the internal data of the game while it's running. For example, this little script for DFHack will show you all notable kills of the selected unit.
Save if as