Feed the pair as two individuals
A bonded pair of guinea pigs shares a home, a hay pile and a social life, but they do not share a metabolism, a confidence level or an appetite. One pig parks itself at the bowl and eats like it is a competition; the other hovers, waits, and makes do with what is left. Balancing their diet starts with accepting that a single shared ration is a fiction — you are running two feeding plans inside one enclosure. The good news is that the three parts of a guinea pig's diet behave differently. Hay can be genuinely communal. Pellets and greens are where the balancing act happens, because those are the foods a bold pig can monopolise.
Hay: the shared foundation that needs no balancing
Hay is the one element you never ration and never need to divide. It should make up the great bulk of both pigs' diets, available in piles at all times, in more than one spot in the enclosure so the shyer pig can eat hay without negotiating for position. Hay wears teeth, keeps guts moving and gives both pigs something to do for most of their waking hours, and its low calorie density means the greedy pig cannot do itself much harm on hay alone. If one pig seems to live at the hay rack while the other eats more of everything else, that is fine — hay enthusiasm is never a problem to solve. Scatter some hay through the enclosure and stuff some into cardboard tubes or paper bags, and grazing becomes a shared activity rather than a scrum at a single rack.
Pellets and greens: measure per pig, serve in two places
Pellets are where portion control lives. Plain, uniform pellets — not muesli mixes, which let pigs pick out sweet pieces and leave the rest — should be measured for each pig separately, roughly a small scoop per pig per day, and served at two feeding stations placed well apart, ideally with a hide or divider between them so the bold pig cannot watch, guard or abandon its own bowl to raid the other. Greens follow the same logic: instead of one pile in the middle, scatter and spread the day's leaves, herbs and pepper pieces across the whole enclosure, in several small heaps, so foraging effort replaces guarding. Vitamin C matters here, since guinea pigs cannot make their own: daily greens should include a reliable source such as bell pepper for both pigs, and scattering is what guarantees the shy pig actually reaches its share rather than watching the bold one eat pepper first. Hand-feeding the shyer pig its choicest pieces during lap time is a legitimate supplement to the system, not cheating — it also builds that pig's trust in people.
Let the scales referee
Appetite impressions lie; weights do not. Weigh both pigs weekly, at the same time of day, in the same order, using kitchen scales and a bowl or small box the pig sits in, and write both figures down. A stable weight in the hearty eater and a stable weight in the picky one means your two-station system is working even if their eating styles look wildly different. A steady slide in the lighter pig across two or three weeks means the shy pig is losing the competition despite your setup: step in with separate feeding sessions, lifting the shy pig out or feeding it in a divided section for its pellet and greens portion before reuniting the pair. Weight loss with a good appetite, drooling, dropped food or a wet chin is a different matter — that pattern points at teeth, and it needs a vet rather than a feeding adjustment. Keeping the weekly weights and the feeding rota together in KinsLe's Care Teams means anyone in the family can run weigh-in day the same way, and the trend for each pig is there to see at a glance.