And are worms always bad? Is there any benefit to removing them if they're present? The answer changes based on so many things, including what kind of worms they are, what the chickens are used for, etc etc.
There ARE some that I'd treat for automatically. Gapeworms and threadworms, for example. Present in any numbers, and I'm treating for them. If I am raising stock, you better believe I'm treating with a coccidiostat starter, and if I had clinical coccidiosis, not treating them could mean my whole flock is wiped out.
The rest, it just depends. If they are otherwise debilitated and have worms, I'll treat them. If they're healthy and have worms, I don't. If they have overwhelming fecal eggs, I'll probably treat them, depending what they are.
Worms are icky. That's true. We don't tolerate them in our dogs and cats or ourselves. Treating livestock routinely without evidence of a problem definitely contributes to resistance to anthelmintics.
Actually, in dogs, there's currently a crisis with resistance to dewormers. Drug-resistant hookworms are going to be problematic in pet dogs in the coming years, and that's not great news. This has emerged because of high-pressure deworming in Greyhound breeding facilities in Florida. Bad practice has led to a coming crisis.