Some homes, especially homes with teenagers, have more Apple devices than house keys. But you need to be signed into different iCloud accounts to track each device. One way around that is to add a single-purpose iCloud account to each device you want to map and track.
iLounge suggests picking one iCloud account in the home (probably tied to mum or dad) and adding that account to each device with only one service enabled: Find My iPhone. You might not have known that you can add a secondary iCloud account to an iOS device. It's useful for the purposes of creating an "Every person, every device" command centre.
The only downside would be if sneaky children went into their settings and enabled sync for your own email and Notes — so a secondary, non-personal iCloud account would be a handy thing to create the next time you pick up a new Apple gift.
The iLounge post has a full step-by-step on enabling a find-only iCloud account.