I am a "yearling" to the "flock habit" so I can relate to your enjoyment!
I have been giving mine ACV since they were about 4-5 months old. I didn't know about it prior to that, so maybe it was good that I didn't, if it messes up their little intestines when given too early. Now, I give them a dose about twice a week in their water which is changed daily. They are fed fermented feed (FF) first thing every morning and moistened pellets with omega-3 supplementation in the evenings.
I have really a healthy flock of over 30 birds. In a year, I have only had 1 hen with a soft shelled problem, and 1 had an eye problem during the winter. They are both well now. Having said that, I think they are doing fine with what I am doing for them. They do get regular calcium supplementation as "free choice" in the hen house. I see them eating it mostly in the evenings before going to roost. I have read that this prepares their egg factory for the next egg coming down the chute! They free range every afternoon until dusk, and put themselves "to bed" if I get tied up with other chores. Everyone loves those delicious golden egg yolks from "the ladies"!
Recently, I hatched some babies... and have 30 viable embryos due to hatch Friday.
I love my chickens...one broody is setting a friend's duck eggs right now...who knows...
I may be a duck lover soon, too!
Blessings to you with your chicks!!!