My logic was like this with lots of assumptions and approximate arithmetic. I assumed there were 30 horses. How much food would these horses eat? Suppose a horse body was 6 feet long and 2 feet in diameter. Then its volume would be approximately 18 cu ft and if a horse was approximately as dense as water it would weigh about 1100 lbs. This makes a horse 7 times as heavy as an average human being. If a human being eats 2 lbs a day then a horse eats 14 lbs a day and 30 of them would eat 400 lbs a day of a ton every 5 days which would be 60 tons in the less than a year.
One question I posed is would anyone notice a one ton discrepancy? Another question is 107 mice a reasonable number. Now assuming that they had a barn where they stored hay and a stable where the horses lived. If the barn were 40 x 60 = 2400 square feet, and each horse had an 8 x 10 foot stall - 30 * 80 = 2400 then there could be one mouse / 48 square feet which sounds plausible.
At dance camp I asked Shana, who is a horse owner, how much feed a horse eats and how much a horse weighs. Robert had previously estimated that these simple questions would take 10 minutes to answer. He might have underestimated, but I was interrupted for some treasurer business after about 7 minutes. Shana explained in her normal expository fashion that you can't answer these questions because every horse is different with differing eating habits, etc. Eventually I got the idea that 1/2 ton was a reasonable weight of a horse, horses were usually shorter than 6 feet, that horse stalls were often 5 x 8 feet, that she uses a 50 lb bag of feed in a bit more than a week to feed her horse and her mule, and a whole lot of other stuff about vets, horse diets, horse care.... So, I wasn't too far off considering that I knew almost nothing about what I was talking about.
In Saturday's strip Raju had a calculator and computed the infestation to be 16.257 (with no units specified so who knows what it means?). In Sunday's strip, the barn looks pretty small and there are two horses in the pasture.
And now back to real life.