Choosing the Right Hay for Guinea Pigs: Timothy, Meadow, and More
Hay is the single most important food for a guinea pig - it should make up most of the diet and be available around the clock. But not all hay is equal. This guide compares timothy, meadow, alfalfa and others, and shows how to pick fresh, dust-free hay your pig will love.
Quick answer
Unlimited grass hay should form the bulk of every adult guinea pig's diet - it wears down their constantly growing teeth and keeps the gut moving. For healthy adults, timothy or meadow hay is ideal. Save alfalfa for young, pregnant or nursing pigs, because it is too high in calcium and calories for adults. Always choose green, sweet-smelling, dust-free hay.
Hay is the single most important food for a guinea pig - it should make up most of the diet and be available around the clock.
Why hay matters so much
Guinea pigs evolved to graze on fibrous grass all day. That constant chewing does two vital jobs: it grinds down their teeth, which grow continuously and can overgrow painfully without wear, and the fibre keeps their digestive system moving. A gut that slows or stops is a genuine emergency in a guinea pig. Pellets and vegetables matter, but they cannot replace hay - a pig that fills up on pellets and skips hay risks both dental disease and dangerous gut slowdown. Hay should be available 24 hours a day.
Grass hays: timothy and meadow
For healthy adult guinea pigs, grass hays are the everyday staple. Timothy hay is the most popular: consistent, high in fibre, and moderate in protein and calcium. It comes in different cuts - earlier cuts are coarser and stalkier, later cuts softer and leafier - and many pigs enjoy a mix. Meadow hay is a blend of grasses and is often softer and more varied, which fussy eaters like. Other grass hays such as orchard grass are useful alternatives, especially if anyone in the home is sensitive to timothy dust.
Timothy and meadow hay suit adults; alfalfa is for young, pregnant or nursing pigs only.
Alfalfa and when to use it
Alfalfa is often sold alongside grass hays but it is a legume, not a grass, and it is much richer - high in calcium, protein and calories. That makes it right for guinea pigs with high demands: babies under about six months, and pregnant or nursing sows. For a healthy adult, though, everyday alfalfa can contribute to obesity and to bladder stones from the excess calcium. Use it as an occasional treat at most for adults, and switch growing pigs over to grass hay as they mature.
Judging and storing hay
Quality varies a lot between batches. Good hay is green rather than yellow, smells fresh and sweet like a summer field, and is free of dust, mould and coarse weeds. Avoid anything grey, musty, damp or very dusty, which can cause respiratory irritation - a real issue in humid Hong Kong and Taiwan homes where hay can go mouldy fast. Store hay somewhere cool, dry and airy, never sealed in plastic where moisture builds up. Buy in amounts you will use while fresh rather than one huge bale.
Good hay is green, sweet-smelling and dust-free; avoid yellow, musty or dusty batches.
Quick FAQs
How much hay does a guinea pig need? Unlimited. Hay should always be available and make up the majority of the diet, roughly a pile the size of your pig each day.
Can adult guinea pigs eat alfalfa? Only occasionally. It is too high in calcium and calories for daily adult feeding and can contribute to bladder stones and weight gain.
My guinea pig is picky about hay - what can I do? Try a softer meadow hay or a different cut of timothy, mix in a little fresh-smelling batch, and always keep it clean and dust-free to tempt fussy eaters.
Does hay type affect the teeth? All long-strand grass hay helps wear the teeth through chewing. The key is plenty of it, all day, rather than one specific type.