And when the bugs arrive, he can turn the chickens lose to eat as many of the bugs as they can. At least it will help.
It sounds like he has already thought this through pretty well.
I also think having a dog is an easy way to keep away chicken predators. Many different breeds will work...
The dog just needs to learn not to chase or bite chickens or people. It will naturally chase after predators.
Find a good dog and the rest comes pretty easily.