I know a commercial poultry man who tried them. At first, he 'went cheap' and got only one. Didn't work, so he ordered more, and mounted them as instructed on their website. Now, he says that they do work.
If you have a secure hen house that the hens get locked into every night, you shouldn't need the cluster-mount (designed for owls/hawks). But at night, coons, possums, weasels, fox, skunks, etc can be persistent enough to find flaws in your design. This night light
may give you some added protection.
Yes, they
can help, but do the math. It takes a
minimum of 4 of them (one on each side of the '
yard', and double that if you are dealing with short AND tall predators) at $20 each. How much does it cost you to raise a hen, and how many can you afford to lose?