rationing chicken feed

So I am shifting toward paddocks for my layers to mix them into some orchard food forest areas and to give them better chicken lives, and in hopes of reducing feed/egg costs.  To date I have been feeding on demand -- I buy in mash from In Season Farms in BC.

I want healthy birds, and want eggs.

How much should I feed daily?
How will I know if they are still healthy?
How do you know if you are not feeding them enough?

Depends on what is in the free range for them, and how their foraging skills are.
For starters, I would give them a very 'light snack' for breakfast, and see how hungry they are when they come home at dusk.

If you give them too much morning feed, they have little incentive to forage.  If they are not used to foraging, their first few days will see them gobble up a lot when the come 'home', but if they are left a little bit hungry, they will quickly learn that there are bugs/plants "in them thar hills".

Play it by ear, but to train them to save you $$ in feed, they need to get a little hungry.  Production may drop for the first week or so, but they should come around.  Once trained, you might be surprised how resourceful they are at feeding themselves (provided you give them access to decent hunting grounds).