Hello &
to the NGA forum!
I have a good amount of deer here but very minimal damage. They don't seem to care at all for my kwanso (ditch lilies) behind the fence at the woodline (although I don't inspect them) but have seen them eat buds from my display gardens on occasion.
I use a lot of Milorganite fertilizer and it seems to be an effective deterrent. Also keeps them away from my hosta. You will want to reapply after heavy rains as they will wash away the scent over time. I have found it at Lowe's and Home Depot.
Even if the deer nibble on your daylilies they won't be killed. They're very hardy! I would advise planting them in a couple of different spots just in case so you won't miss blooms if deer do become a problem.
Good luck and happy (daylily) gardening!