I'm going to think out loud for this one:How many animal units would it take to sustain a farm for a jiffy?
1. "Animal units" - don't think I've heard this before, but maybe it's a male-female pair of animals? Nah, usually there are more females than males on a farm (I think). Okay...I'm going to assume that an animal unit means one animal over the course of its lifetime. This makes sense to me in that a farmer could buy "animal units" to stock his or her farm.
2. "Jiffy" - I have heard this before, but I don't recall how much time it is. Maybe something like a tenth of a second? That's what I'll assume.
3. "sustain a farm" - I'm going to interpret this as "maintain the animal population levels on a farm."
Computation, guessing at several of the factors, desired units are: animalUnit/farm-jiffy
(1 animalUnit / 5 animal-year) * (1 year / 365 day) * (1 day / 9E3 sec) * (1 sec / 1E1 jiffy) ~= 1 animalUnit / 2E8 animal-jiffy
(1 animalUnit / 2E8 animal-jiffy) * (1E4 animal / farm) = 5E-5 animalUnit / farm-jiffy
I'd guess I slightly overestimated the number of animal/farm, so I'll go with Fermi Answer -5.
@syo_astro, sounds like you have a solution in mind? close at all? Time for me to go google animal unit & jiffy
How many seconds would it take a common snail to travel from Paris to Istanbul?