Dang! I occasionally give my llamas alfalfa pellets....have to be careful about that!
I've read about llamas choking on pellets but they never say what size of pellet. Around here the only choices are a large horse cube or small 3/8" pellets. I give mine a couple handfuls mixed with grain twice a day when hunting to supplement the grass. Some suggest putting a few golf ball sized rocks in the feed pan to slow down their eating and make them take smaller bites.
A llama's digestive system is completely different than a horse's. They're semi-ruminants as they have a 3 chambered stomach. They can pack in a bunch of feed then chew it later like a cow. As long as they eat slow enough for the feed to get down the pipe without clogging, they can handle it.
