How to build a monthly feed shopping list for a mixed hobby farm

Step 1: count the animals and weigh the ones where weight matters

The sample household is the calculators’ starting values: 6 standard laying hens, 2 guinea pigs at 0.9 kg each, 2 adult rabbits at 2.5 kg each, and 1 horse of 1,102 lb (500 kg). For hens the count is enough, because the published figure is per bird. For rabbits and horses the amount is per kilo of animal, so a 2.5 kg rabbit and a 5 kg one are two different lines; weigh them on the bathroom scales, and tape or weigh the horse rather than guess.

Step 2: write down what each animal eats in a day

Every line comes from a published feeding figure with its source and date: the chicken guide gives 4.0 oz (113 g) of complete feed per hen, the guinea pig guide and the rabbit guide give hay, pellets and vegetables per animal, and the horse hay guide gives hay as a share of body weight plus what is wasted. Multiply each by the animals and you have the day.

The horse line is already the amount you put out, not the amount eaten: 2% of body weight a day (University of Maryland Extension, Calculating Your Horse's Winter Hay Needs (7 Apr 2021), 2026-09-19) divided by one minus the 13% wasted on the ground (Penn State Extension, Buying Winter Hay for Horses (27 Oct 2025), 2026-09-19). Hay for the small animals is unlimited in the hutch; the figure is what “unlimited” comes to for the shopping list.

Step 3: scale the day to a month

A month is 30.44 days on average (365.25 / 12), and the calculators use that rather than 30, so twelve monthly lists add up to a year. The hens' 1.5 lb a day becomes 45.7 lb a month; the horse's 25.3 lb a day becomes 771 lb. Keep the monthly figures in kilograms or pounds at this point; the rounding to whole bags comes next, and rounding each species first would lose the fractions you want to add up.

Step 4: turn kilograms into bags and bales

Divide each monthly amount by the weight of the package you buy and round up: a fraction of a bag is a whole bag at the till. The package sizes here are the calculators’ starting values for the US, each from a retail page; change them to what your store sells. Vegetables and greens stay in kilograms, because nobody buys them by the bag.

The rounding is where a list beats four separate sums. The hens use 0.9 (buy 1) bags of layer feed a month, so one bag every 33 days; the guinea pigs’ pellets come to 0.2 (buy 1) of a 5 lb bag, one bag every 180 days, so you buy that bag once and skip it on most lists. The horse’s bales are the opposite: 19.3 (buy 20) a month, a 40 lb bale every 2 days, which is a delivery, not a shop run.

Step 5: price what has a price, type the rest

Only one line on the sample list carries a published price: layer feed at $15.00 a 50 lb bag (University of Maryland Extension FS-2025-0783, Backyard Layer Flock Economics (page dated Aug 2026), 2026-09-19), which makes the hens $13.70 a month and $164 a year. Hay, pellets, vegetables and bales have no neutral published price, because they vary by region, shop, cut and season, so the calculators leave those cost cells empty until you type a price. Do it once, from your last receipts, and the list carries a monthly total from then on; the chicken feed cost guide shows how far a bag price moves the total.

Step 6: mind the seasons

The bales are the seasonal line: 19.3 (buy 20) a month applies to the months you feed hay, and the calculator's starting value is a 5-month winter (Penn State Extension, Buying Winter Hay for Horses (27 Oct 2025), 2026-09-19), which is 96.4 (buy 97) bales to buy or store before the grass stops. Hens eat more in cold weather and less when they free-range in summer, and rabbits and guinea pigs eat grass in a run that replaces part of the hay. A monthly list is the right rhythm because of this: redo it at the start of each season rather than once a year.

Keep it up to date, or let the plan do it

The honest way to keep the list right is to weigh what you put out for a week each season and type that into the calculators instead of the averages. The four calculators save what you type in your browser; the Pro plan reads those saved inputs, runs this same arithmetic for the whole household on one page, and exports the list as a spreadsheet with the formulas in it, so a change to one number changes the bags, bales and total.