@centrarchid
I am ID'ing much further than a spotlight can be useful, though I do have a spotlight for when I am going out into the yard at night to check on things.
I also asked if you have a red or green filter on your spotlight.
The coops are about 100' from the house and the rifle may be used for shots from ~75' to over 200 yards so the scope stays on all the time, rendering it a bit useless for nighttime shooting without a headlamp. I have a very good headlamp that doubles as my egg candler and I may see if I can find some red or green filters for it.
I can't imagine what is more cost effective than a bullet, but I'm sure your situation (predator load and their habits) are different than mine. I live on a tiny peninsula off of a larger peninsula, so overabundance occurs after each mating season, there is little to no competition for the foxes, and short of food shortage or disease overload there is not much to limit the population, which explodes each year. However, elimination of any foxes that I see on my property or the surrounding farm fields (which is undoubtedly a very small part of the area's population) is very effective; if I have knowledge of a fox scoping out or attacking my birds and I get rid of it, I can usually get 3-4 months of down time before another shows up as long as i keep an eye on the surrounding farmfields. And yet, also no flare up in rabbits, rodents, or other typical prey animals that the foxes should keep in check. The raccoon population seems to be relatively low out where I live. I have trapped one that was visiting my coops trying to figure out how to get in but that's the only one I've ever seen. One did kill one of my Toms but I think it was the same individual.
I don't think I have spent all that much on predator ID/deterrent/control... Wire skirt around the perimeter of the run (cost unknown, some was given to me for free)...heavy duty netting over the run ($65)...two game cameras (cost >$100 total for both)...$0.75/shell for the 204...$35 for two live traps. Still, I would like to hear about the other measures you allude to.