Mine constantly stalk us through the patio doors & even jump up to check up on us through the kitchen windows.
I think it's admirable that you're trying to find ways to extend the life of your chickens! I think a lot of people take chickens for granted as disposable and that makes me sad.
Definitely breed - Stay away from production sex links bred for egg production and also Cornish crosses bred for meat.
I feed mine Scratch n Peck layer feed since all my ladies are laying.
I "ferment" it by mixing it with water in batches 1-2x per week & then feed as I go. They definitely like it over pellets because they like picking out the seeds. But the water helps bind the fines into a kinda paste so they get all of that goodness too.
Free ranging will definitely leave them more exposed to predators. But mine are definitely happier that way. They squawk loud & long enough to raise the dead when they're cooped up in the run on really bad weather days.