Table 1.

Ethogram for coding homecage video recordings following treatment procedure. The ethogram was adapted from existing publications [20,30,31] and from pilot observations. The behaviours are listed in alphabetical order. Behavioural coding was done on one individual mouse at a time, so each video clip was observed twice to allow behavioural coding for both mice in a cage. Point events were recorded as frequencies only, whilst states were recorded as both frequencies and durations.

Behaviour	Behaviour Type	Description
Aggression	State	Mouse demonstrates one or more of the following behaviours: Chasing—focal mouse follows the same path as cagemate, cagemate is fleeing, both mice are running; Tail rattling—focal mouse waves tail side to side in fast almost vibrating motion; Biting—mouse attacks the cagemate with open mouth, appears to bite or latches on to recipient; Boxing/parrying/thrust—movements towards one another, kicking with forepaws.
Allogrooming	State	Focal mouse uses paws and/or mouth to brush, lick or nibble the fur of cagemate.
Body shake	Point event	Mouse rapidly shakes its whole body, as if to rid its coat of dust.
Climbing	State	Mouse hangs from the cage lid, with the forelimbs or all limbs gripping the lid bars.
Eating/Drinking	State	Mouse has its mouth touching food hopper or food pellet, with chewing movement of the jaw, or mouse has its mouth touching the water outlet.
Facial grimacing	Point event	Mouse demonstrates one or more of the following pain descriptors: Mouse shows orbital tightening/narrowing of the eyes (not in the context of grooming, because mice narrow/close their eyes to groom); Bulging on the bridge of the mouse’s nose and/or wrinkles on the side of the nose; Bulging of the cheeks; or Ears rotate outwards and/or backwards. Ears may fold to form a pointed shape. Space between the ear increases. (Whisker placement would normally also be included but it was not possible to see this level of detail in the footage.)
Freezing	State	Mouse makes no movement (except for slight head and/breathing movement), for at least 2 s.
Self-grooming (not including ears or tail)	State	Mouse demonstrates two or more of the following descriptors: 1. Mouse licks its forepaws; 2. Mouse makes repeated strokes along the snout with both forepaws; 3. Mouse makes semicircular movements over the top of its head and behind the ears with both forepaws; 4. Mouse licks or grooms its fur on its anterior part of the body and/or scratching with the hind paw; 5. Mouse licks or grooms its hind legs; 6. Mouse licks or grooms the genitals; 7. Mouse scratches any part of the body (other than the ears) with its hindpaw, a move isolated from the cephalocaudal grooming sequence.
Grooming left/right ear	Point event	Mouse strokes/scratches the left/right ear with its forepaw or hind paw.
Grooming tail	State	Mouse sniffs or licks its tail while holding it with both forepaws (isolated from the normal cephalocaudal grooming sequence).
In tunnel	State	Mouse has all four limbs in the shelter—behaviour is visible.
Not visible (tunnel)	State	Mouse is in the tunnel but detailed behaviour is not visible.
Not visible (other)	State	Mouse is located at a spot where it is hidden from scorer’s view (e.g., behind the food rack).
Other active behaviour	State	Collection of active behaviours not otherwise recorded, such as walking, sniffing, digging and gnawing.
Rapid shuttle	Point event	Mouse flits extremely fast from one location of the substrate to another.
Rearing	Point event	Mouse lifts its forepaws off the ground, mouse has its forepaws on the cage wall/shelter, only standing on its hind legs,
Sniffing cagemate	Point event	Mouse pauses and extends neck to touch cagemate with its nose. May also lightly touch the area with forepaws.