How do you think the Yeerks kept their Hork-Bajir fed between the invasion of their homeworld and the Earth invasion? The one world we're sure that they invaded was the Taxxon homeworld, which was supposed to be mostly desert, likely with minimal trees and tree bark. If the Yeerks really would end up destroying the natural beauty of planets that they conquered like Ax says in Book 4, I can't imagine feeding all the Hork-Bajir would be easy. Unlike Taxxons, who eat anything.
All right, so. You can get up to 12 square yards of mulch from Home Depot for $560 in today's dollars, which is $285 in 1997 dollars. We don't know exactly how many hork-bajir-controllers are left after Alloran's ethnic cleansing, but from Visser I'm guessing it's a few hundred to a couple thousand. Of those, not every one is posted on Earth, so I'm willing to bet there are only ~1000 hork-bajir on Earth.
How much does a hork-bajir eat? Well, an Earth animal that's about 7' long and herbivorous — I'm going with okapi — eats about 35lbs of plant matter a day. A cubic yard of mulch weighs about 600lbs, according to Home Depot. So 1 cubic yard of mulch is about 17 days' food for one hork-bajir, or 1 day's food for 17. Which means you could get 204 days' food (12*17) out of $285 in 1997.
If there are 1000 hork-bajir, then you'll need 5 of those 12-yd shipments a day, which comes out to $1425 in then-dollars, $2802 in now-dollars. UNESCO says that cheap bulk meals for humans can be calculated at $3 a meal or $9 a day with U.S. ingredients, meaning it'd cost a nonprofit ~$9000 a day to feed 1000 humans. So if feeding a human costs about $9 a day and feeding a hork-bajir costs about $2.75 a day in today's money, then I'd say they're probably feeding the hork-bajir just fine. I'd even venture that they're spending more on the "grilled chicken, roast potatoes, steamed broccoli" (Visser) the humans get than on their hork-bajir.










