What are some good ways to ensure my older chickens are comfortable and healthy?
Using a flock raiser or grower feed (with 18-20% protein) formulated ration with oyster shell on the side free choice... more protein and
amino acids in the feed and they take the calcium they need verses "layer" and not being able to avoid calcium during molt and such... especially since all your ladies (in your signature line) are dual purpose breeds. Don't feed treats in excess of 10% total daily intake as diminished nutrition can also diminish immunity. Beyond that I disagree about them needing to be watched or supervised more as they get older. Since making the switch permanently my birds enter molt less harsh than when I used "layer" and return to lay sooner... as they appear to have more nutrient reserves on board to deal with stress the difference in their personality during molt is huge. It also translates into more nutrition inside the eggs.. you are what you eat. If you already do this, then keep it up...
Make sure roosts aren't to high and landing isn't too hard... soften with hay, shavings, etc... to prevent bone and joint jarring and foot or leg injuries.
Check monthly for angry red skin or clumps on feather shafts, below or around the vent (preferably after dark with a flash light as it give the best picture) and treat for parasites IF needed. Doing a group fecal float... multiple fresh samples from multiple birds... can give you an overall look at internal parasite load for your flock to determine IF they need any treatment and ensure the right medication is used to treat the correct parasite,,, IF needed. There are some mail in places that may be cheaper than your local vet. It cost about $28 at my local vet, which is fairly pricey. This avoids giving unneeded poisons, wasting money, time, energy, etc.
This monthly evening check will also give the chance to notice any water belly/ascites, vent gleet.. type symptoms. Any penguin stance or separating from the flock in daytime is cause for alarm. As well as sleeping ion the nest box, if it's out their norm.
Beyond that.. general good husbandry practices like keeping ammonia smell down and plenty of ventilation, a dry place to dust bathe, fresh potable water, dry shelter, and source of grit...
The BIGGEST suggestion.. do NOT bring in birds from someone else's place!!! I cannot stress this one enough. If you add new birds... go with
chicks from an NPIP seller or hatchery.
I think my oldest (pet) ladies just turned 3 this year... seems like they are in the prime of their lives! So while 3 is considered older in industry terms, for home keepers, they're just middle age.

My breeding stock always gets a couple older birds replaced with a couple younger to constantly improve and also to have eggs during winter. But if you plan ahead and don't have space for new additions... eggs will stay fresh, unwashed in the fridge for MORE than 6 months!
My friend has some 4-5 year old Wyandotte and Orp ladies that sport spurs these days, Pics always welcome.
