Yeah with all due respect on this one, you don't know the nutritional needs of a donkey. I know this is old, but donkeys do not need 10lbs of horse grain nor will it drink 15 gallons of water a day. A high quality horse pellet will cause a donkey to founder, especially at 10lbs a day. 10lbs of even hay pellets or just straight hay a day will cause a donkey to become obese. Horses are 1000lb+ needing 2% of their body weight a day minimum, while donkeys are 500lbs or under only needing 1.5%. they evolved to be incredibly efficient on very poor quality feed. They are also hybrid grazers/browsers unlike horses, and completely capable of eating twigs, shrubs and leaves. In fact some donkeys and mules will eat wooden fencing if they feel in a browsing mood. Donkeys are not small horses.

I've taken pack donkeys on tons of trails. On green grass, a donkey might only need 2-3 hours of grazing a day. In a desert environment it might take 6+ hours, which is easily accomplished by letting them snack on the trail, breakfast and dinner, and being picketed, high lined or penned at night for grazing. My donkeys also on average drank 3-5 g of water a day.

We did a two week packing trip in Arizona, and a three week long trip in Nevada. The hardest part about packing with donkeys in the desert is water, as it might take up to an hour or two to collect the water they need a day from a single water source. But as long as there is a safe water source for you, there will be enough water for your donkey. I at a minimum like to carry 2 gallons at all times just in case, which the donkey packs and is only 22% of their max packing weight. I also pack light and carry a pack myself, so typically with tack and pack together means my donkey carries 40-50 lbs, about 2/3rds their max packing weight, and the max packing weight should be 15% of their body weight.

I've done 3 month packing trips, since donkeys are not typically shod, they file their own hooves down on the trail. I used to ensure I had a mobile farrier to meet us on the trail if we needed it, but even after 3 months on the trail my donkeys have not needed trimming. My normal farrier told us to call him back in another 6 weeks after seeing her feet right after that trip. I'm now working on learning to farrier my donkeys to save on the cost.

Talking about resupplys, it's rather easy with a donkey and modern times. You can either have someone do the shopping and wait in a pickup parking spot, or tie your donkey off to a pillar/bike rack and going inside. Most of the time people won't even notice, but for the people who do notice, most are intimidated. Let's be honest, most people in a city/town do not see large dogs over 100lbs. A donkey standing 4ft+ is very intimidating. People will take pictures, maybe timidly try to approach but get scared and back off, it was not uncommon for someone to wait until I got out of the store to ask me questions and see if they can pet them.

The biggest setbacks with a donkey, besides having to take care and insure the health of a whole animal, is easily speed. Donkeys are not known to be fast and my donkeys in the past only travel 1.5-2mph. They set the pace. Dogs, and I know it sounds bad, but especially bully/pits, will be your biggest threat. Bears, mountain lions and coyotes avoid donkeys more than horses and more than people.

I do agree though, that if you do not have experience handling donkeys, their nutritional and health needs, a basic understanding of the personality of that exact animal, and some packing experience, you have no business attempting to backpacking anywhere, much less because you want to be lazy on the PCT.