Hi, welcome to BYC!
So as long as they have some grit available... I can share my experience...
I have been raising chickens for about 9 years now and never wormed the first 8 because I didn't know you MIGHT need to. My birds have always free ranged and eat every bug they want including earth worms/red wigglers. Really age has nothing to do with it. Many of my chicks are on pasture by 3 days old, especially if they are with their mum's.
I have 1 gal who has always had mud butt. Then I saw one of my dogs come in and scoot their bum. Both signs many people will SWEAR is worms. Since I don't believe in treating what I don't have and not treating what I do... and not all wormers treat all worms, and the ONLY worms that will be seen in droppings are large round worms and tape worms while all others stay living in the digestive tract and just their microscopic eggs (oosysts) will pass and never be seen...I prefer to do a float test first. So off to the vet with with a "flock" sample and "pack" sample in hand... many samples combined into one for the same species makes a more affordable way of testing and is an accepted method to get an overall look... cost $25/ float at my vet. Even though I pay for a float, I don't pay for a poison that won't treat what I don't have and expose my birds to it needlessly, and I don't lose out on eggs being withheld for no reason. Not to mention my time and effort.
Long story short... both samples came back negative for worms and cocci. Turns out sometimes dogs have their bum itch or their anal gland annoy them and scooting is a way they deal with it. Also SOMETIMES a bird just has digestion issues.
So in 9 years of my birds consuming earth worms... I don't have the others. That isn't to say you won't... not all environments are the same, even if you have good pasture maintenance and biosecurity practices... it COULD happen. I suggest having float done at least once per year. Twice is nice. And get familiar with your actual load and if you see any seasonal difference. And I would treat ONLY as needed.
My suggestion... try not to worry so much, but awesome to know the possibilities and be aware of any changes in your birds.