Senior food for two Terriers at different weights

Two terriers at different life stages and different weights — that's a genuinely tricky feeding situation, because you need a senior formula that suits both without overfeeding one and underfeeding the other. Senior dogs really do need different nutrition: fewer calories, easier digestibility, and ideally some joint support. But before I point you toward anything, it helps to know the specifics. What are the two dogs' current weights, what are they eating now, and does either have any health issues I should factor in?

That stiffness in the Scottie is worth taking seriously — at 10, joint support becomes a real priority, and adult kibble just won't deliver enough glucosamine and omega-3s to make a meaningful difference. The Cairn at 8 is technically entering senior territory for a small breed, so switching both now makes good sense. The key challenge here is portion control: you need a food that's appropriate for both, and then you manage the weight difference entirely through how much each dog gets. What I'd recommend is Royal Canin Mini Ageing 12+ — I know the age bracket sounds like it's for older dogs, but for small breeds like Scotties and Cairns the nutrient profile is genuinely right from around 8–10 years onwards. It's calorie-controlled, has added joint support, and the small kibble size is perfect for terrier jaws. You'd just feed the Cairn to the lower end of the weight band and the Scottie to his own. Do they eat in the same room, or can you separate them at mealtimes?

Yes, absolutely. Royal Canin's age labels on their small breed range are a bit conservative — the nutritional profile is designed around the needs of ageing small dogs, and a 10-year-old Scottie is well into that bracket. The joint support ingredients, the digestibility, and the calorie density are all exactly what you're after. The '12+' refers to Royal Canin's own classification threshold, not a hard minimum. For a 9.5kg Scottie showing stiffness, this is a solid fit. You'd feed him towards the higher end of his weight band to make sure he's getting enough of the joint-support nutrients. And the Cairn at 6kg slots neatly into the lower portion guidance. Since they're relaxed feeders, you should be fine keeping them in the same room — just use separate bowls and measure carefully.

Take about 10 days. Start with roughly 25% new food mixed into 75% old, then move to 50/50 around day four, then 75% new by day seven, and full switch by day ten. Terriers can have sensitive stomachs, and the Scottie breed in particular is prone to digestive upset if you rush it. If either dog gets loose stools at any stage, just slow the transition down rather than going back to square one. Once they're fully on the new food, give it six to eight weeks before judging whether the Scottie's stiffness has improved — the joint support takes time to build up.

Great — it's a genuinely good match for both of them. Keep an eye on the Scottie's weight over the first month, as the calorie reduction from switching off adult food can occasionally cause a small dip if he was eating a larger portion before. And if the stiffness doesn't ease at all after a couple of months on this, it's worth mentioning to your vet — sometimes a short course of prescription joint support is needed alongside the diet change. Good luck with the switch.