A cup a day, measured by eye once you learn it
Picture a mug filled loosely with chopped vegetables: that is the daily fresh allowance for one adult guinea pig. Weigh or measure it properly the first few times so your eye learns the amount, because a generous handful grows over weeks when it is never checked. Two smaller servings, morning and evening, suit most households and keep vegetables from wilting uneaten in the bedding for hours.
Young, growing and nursing guinea pigs may eat a little more, and a guinea pig on a weight plan keeps the leafy cup while the extras around it shrink. The cup is a guide to the vegetable portion only — it never replaces hay, which should be eaten in far greater volume across the day and night, and it sits beside a modest measured portion of pellets rather than competing with them.
Build the cup around leaves and vitamin C
Leafy greens should fill most of the measure: romaine and other lettuces, coriander and other herbs, and leafy tops all make good foundations. Each day include something rich in vitamin C, because a guinea pig's body cannot store much of it and scurvy develops on a diet that looks plentiful but lacks that one element. A chunk of bell pepper is the easiest daily answer, with leafy greens contributing alongside. Rotate two or three other vegetables through the week — cucumber, courgette, a little broccoli, green beans — so the diet varies without any one item being fed in large amounts day after day.
Introduce every new vegetable in a small piece first and watch the droppings for a day. Soft droppings after a change mean the novelty or the quantity was too much; return to the familiar mix and try again in smaller amounts. Wash vegetables, serve them at room temperature rather than fridge-cold, and lift out anything uneaten after a few hours so it does not rot in the hay.
What stays occasional, and why
Fruit is dessert, not a vegetable serving. Its sugars make a small piece of apple or a berry a treat for once in a while, not a daily cup-filler, and the same goes for carrot, which is sweeter than its savoury reputation suggests. Iceberg lettuce is mostly water with little nutrition, so if it appears at all it should be a minor part of a mix led by better leaves. Avoid onion, potato and rhubarb entirely, and be cautious with large amounts of cabbage-family vegetables, which can leave some guinea pigs gassy and uncomfortable.
Dried mixes with seeds and coloured pieces are not fresh food and do not count toward the cup; they belong, if used at all, in the measured treat column. When in doubt about a new item, leave it out until you have checked it is safe for guinea pigs specifically, since foods fine for rabbits or hamsters are not automatically fine here.
Serving habits that keep the cup honest
Serve vegetables in a clean dish or scattered through clean hay for a little foraging, and make sure bonded guinea pigs each get their share — a confident pig will eat two cups while a shy one watches, so two dishes or a spread-out scatter protects the quieter animal. Check at the next feed what was actually eaten; persistent leftovers of one item tell you the rotation needs adjusting, not the amount.
If appetite drops, droppings shrink, or your guinea pig leaves even favourite foods, treat that as a health sign and contact a vet rather than tempting with ever sweeter extras. Through KinsLe's Care Teams, the daily vegetable preparation can be assigned and ticked off, keeping one measured cup the household standard instead of each person's guess.