A walk-in height, not a hop, for a Devon Rex
For an older Devon Rex, the entry side of the litter tray should sit about two to three inches above the floor. That height lets her step through with a level back instead of gathering herself for a small jump. The Devon Rex is a small, fine-boned cat with large ears and a wavy coat, and she carries little spare muscle in her hindquarters. When her hips or back stiffen with age, a standard tray wall that once meant nothing becomes a hurdle she has to plan around. Keep the other three sides at normal height so litter stays inside when she digs, and lower only the side she actually uses.
Why a light, slender cat struggles quietly
An older Devon Rex rarely announces joint stiffness with a dramatic limp. Watch instead for the pause before the tray, front paws placed on the rim while the back end catches up, or litter scattered in a trail because one hind paw clipped the edge on the way out. Her slim build means there is less muscle to compensate when a joint hurts, so a failed or awkward entry can quickly teach her to go beside the tray instead. That avoidance looks like a behaviour problem, but in a senior Devon it is often a cat making a sensible decision about a barrier that has grown too tall for her body.
Setting up the low entry so it actually works
Cut or choose the entry on a short side of the tray, and make the opening wide enough that this Devon Rex does not have to angle her shoulders to pass through. Sand or cover any cut edge so nothing sharp meets her belly as she steps across. Place a firm, non-slip mat directly outside the opening, because her fine paws can skid on hard flooring when she steps down with litter dust on them. Keep litter depth moderate inside the tray: a very deep fill raises the inside floor unevenly and makes her footing spongy, which adds balance work for a cat who is already managing stiff joints.
Reading the tray for early warnings
An older Devon Rex who starts leaving deposits just outside the entry is telling you the step still costs her too much, even if she manages it some of the time. Check whether she uses the tray happily at certain hours and avoids it when she first wakes, when stiffness is usually worst. Note paw prints and scatter patterns for a few days after lowering the entry, because cleaner landings are an early sign the change helped. If she cries out stepping in, stops using the tray altogether, or seems unable to posture comfortably to pass urine or stool, that is the point to book a vet visit rather than keep reshaping plastic.
Small placement details that matter for this breed
Put the low-entry tray where this Devon Rex already prefers to go, on the same floor as her sleeping and feeding spots, so she never faces stairs plus a rim in the same trip. Devon Rex cats feel the cold through their short, wavy coats, so a tray parked in a chilly, draughty corner adds one more reason for a senior to hurry and strain. A quiet, warm, ground-floor spot with the tray opening facing her approach path removes friction she cannot afford. Recording the entry height, tray position and the date her use improved in KinsLe Pet Passport means that senior-care detail travels with her records to vet visits, boarding stays and sitter handoffs.