I've had the best luck with the deer eating the "Allstock" pellets from Dels's more than other pellets. I'm not sure if I have used pure alfalfa though. I always add some apples to my pellets when starting each year, I think this gives them the idea that these might be good to eat. I haven't baited elk. I pretty much feed the deer these to help in the winter, I bait with apples.
I made a covered feeder for my pellets to keep the rain off, plus, I have the luxury of only needing to put out a limited ammount at a time.