Four cats of very different ages do not need one garden rule; they need a garden where hazards are removed for everyone, escape routes are engineered down, and supervision matches the individual cat most likely to test a boundary or least able to cope beyond it.
Remove the True Hazards First
Start with what can injure any cat regardless of age. Lock slug treatments, weedkillers, fertilisers and antifreeze-type products in a closed shed or cabinet no cat can enter, and never use rodent poison anywhere on the property, because a poisoned rodent becomes a poisoned cat's meal. Cover water butts tightly, and give ponds a shallow, rough-surfaced slope at one edge so a cat who falls in can climb out rather than scrabbling at a vertical side. Check bonfire piles and log stacks before lighting, move sharp tools off the ground, and fence off any compost or garden machinery area. Walk the whole garden at cat height once, looking for gaps under gates, loose fence panels and holes a kitten-sized body could use even when adult cats cannot.
Engineer the Boundary, Then Supervise by Cat
A fence that leans inward at the top, or carries a smooth roller along its length, defeats most climbing exits because the cat's own weight turns it back into the garden. Fit it around the full perimeter with no tree, shed roof or bin bridging over the protected line, since one launch point undoes the rest. Even a well-engineered boundary is a reduction in risk, not a guarantee, so match freedom to the cat: a confident young adult may use the garden freely within it, while a kitten, a frail senior or a newcomer starts with supervised sessions or a harness and long line until habits and recall in that space are proven. Harness time should be the cat's choice to move and explore, never a tether left unattended.
Make Staying In More Rewarding Than Leaving
Cats roam looking for what the garden lacks: shade on hot days, shelter in rain, high viewpoints, hunting interest and quiet resting places away from busier cats. Provide all of them inside the boundary — a shaded platform, a dry sheltered bed, planted cover, and separate resting spots so a senior is not displaced by a younger cat. With four cats, territory friction pushes the loser outdoors, so watch who controls the best spots and add duplicates where tension gathers. Feed and play in the garden at regular times, building a routine that brings every cat back to a known place daily, which also makes a missing cat obvious within hours rather than at bedtime.
Accept and Plan for the Risk That Remains
Honest planning admits the remainder: a gate left open, a determined climber, a delivery propping a side door. Keep collars and identification current for every cat who goes out, keep a recent clear full-body photo of each, and know each cat's hiding habits, because a frightened cat usually hides close and silent rather than travelling far. Agree in the household who checks the garden last, who counts cats in at dusk, and what the first call and first search look like if a count fails. Rehearsing that response on a calm evening is what makes it usable on a frightening one.
A Safety Net Beyond the Fence
Layered prevention still deserves a recovery layer ready before it is needed, with photos, descriptions and contact details prepared for all four cats rather than assembled in a panic. If the worst happens, an alert sent via KinsLe reaches nearby owners in Lost Pet Alert System coverage, while a finder who spots your cat can contact you directly without delay.