A guinea pig stock system fails when it asks for too much. Weighing hay to the gram lasts a week; a five-field table updated during the weekly clean lasts for years. The design below uses three stock lines, one each for hay, pellets, and fresh food, and the same field set on every line, so you learn one small habit and apply it to everything your pigs eat. The running balance is kept in days of supply, not weight, because the question you actually need answered on a shopping day is how soon you run out.
One Field Set for All Three Lines
Every entry on every line carries the same five fields, in the same order: date, item, amount bought, amount used, running balance in days of supply. Date is the day you write the entry. Item names the specific food, such as timothy hay, plain pellets, or bell pepper, rather than a vague note like greens. Amount bought records what came into the house, in the units you buy it in, such as one bale bag or two heads of lettuce. Amount used records what the pigs actually consumed since the last entry, in the units you serve, such as two handfuls of hay or half a pepper. Running balance in days of supply converts what remains into time: at the current rate of use, how many days before this line runs out.
Here is a worked example entry carrying every field with a real value, written for the hay line: date Monday, item timothy hay, amount bought one bale bag, amount used two handfuls, running balance nine days of supply. Read it back and it answers everything at a glance: on that date the new bag arrived, two handfuls since the last entry is the current pace, and nine days is when you must shop again. Write one such entry per line each week, at the same sitting, and the three balances together become your shopping list: any line at seven days or fewer goes on the list that week.
Running Each Line the Way That Food Behaves
Hay is the continuous line. Guinea pigs eat hay at all hours for digestion and tooth wear, so track it in handfuls per day as you actually serve it, and expect its balance to fall steadily rather than in meal-sized steps. Pellets move slowly and predictably, measured in the small daily scoop you serve, so their balance is the easiest to forecast and the line where a falling balance most often means you have been scooping generously. Fresh food is the fast, variable line: it is bought in small amounts, spoils quickly, and varies by what looked good in the store, so enter it at the same weekly sitting and accept rougher figures, because its job is to flag waste and favorites rather than to audit every leaf.
Notes, Reviews, and Handing the System Over
The observations that save money later are which greens were eaten eagerly, which were refused and wasted, and when a supplier changed quality or price — hold them in mind at the weekly review, because the five fields stay exactly five. Review the three balances together each week while you weigh your pigs, so stock, appetite, and health sit in one habit and a pig who is eating less shows up in both the weight note and the slowing hay line. A paper notebook kept beside the cage works as well as a spreadsheet for most homes; what matters is that the fields never change, so entries stay comparable month after month and a sitter can read the system cold. Kept beside the pigs' health summary, KinsLe's portable record in Pet Passport means a new helper sees stock levels, favorite greens, and recent weights in a single packet.