Switching guinea pigs to hay-based diet

Switching adult guinea pigs from a pellet-heavy diet to a hay-based one is genuinely one of the best things you can do for their long-term health — pellets are often over-relied on, and unlimited high-quality hay should make up around 80% of their diet. That said, two-year-olds who've grown up on pellets can be a bit resistant at first, so the transition needs to be gradual. Before I point you toward the right hay, can you tell me: are they currently eating any hay at all, or has it mostly been pellets? And are they at a healthy weight right now?

Good starting point — they already know what hay is, which makes this much easier. The key is to gradually reduce pellet portions over three to four weeks while making hay continuously available, so they naturally eat more as pellets become scarcer. The hay you choose really matters here. Silkies are the same as other guinea pigs nutritionally, but their long coats mean you want to watch for hay getting tangled in their fur — loose, fine-stemmed hay is better than coarse stalky varieties. What are you currently feeding them in terms of fresh veg alongside pellets?

That's a solid veg mix, especially the bell pepper — that's your main vitamin C source, which matters because guinea pigs can't synthesise it themselves. Keep that going throughout the switch. Now, for the hay itself: the product I'd point you straight to is Oxbow Western Timothy Hay. It's the benchmark for adult guinea pig hay in the UK — consistently fresh in the bags that stock well on Amazon, soft enough not to tangle badly in Silkie coats, and the fibre profile is exactly right for dental and gut health in adult pigs. Buy the larger bags (around 1.13kg) rather than the small ones — you'll get through it, and fresher-smelling hay gets eaten more readily. Place it in a hay rack rather than on the cage floor so it stays clean and they're actively pulling at it.

A small daily portion of pellets is fine to keep long-term — roughly one to two tablespoons per pig per day once you've completed the transition. This just acts as a nutritional top-up and gives you a predictable moment to check each pig is eating normally. Going completely pellet-free is done by some owners, but it's a bigger commitment to diet monitoring and isn't necessary. The real goal is just flipping the ratio — hay as the foundation, pellets as the supplement rather than the other way round. At two years old and healthy weight, your Silkies should adapt well within a month.

Yes — weigh both pigs weekly during the transition. A small digital kitchen scale works perfectly; just pop them in a bowl. Any weight loss of more than 50–60g over a week is a signal to slow the pellet reduction and check they're actually eating the hay. Also watch their droppings — they should stay firm and plentiful. Fewer droppings or very small ones means gut motility has slowed, which can happen if hay intake hasn't picked up yet. If that happens, pause the transition and let them stabilise before continuing. Both of those are easy to spot early, and catching them early means nothing serious develops.