It's a big space but there's not anything for the chickens to do other than eat. Since you have the room for it, I'd add a ton of clutter - doesn't have to be anything fancy, just scrape up junk from around the yard like large pots, pallets, wheelbarrows, patio furniture that you don't mind...
Current photos of run would help - mainly what I'm looking for is clutter: https://www.backyardchickens.com/threads/a-cluttered-run.1323792/page-6#post-25037140 to provide hiding spaces and to keep birds busy. Since you already feed a high protein feed and minimal treats, protein sounds like it...
Can we see photos of the actual coop and run? Size of the facilities is only one consideration.
Since you mentioned vacation and that they were being cared for by a neighbor for a week, did they follow a set schedule that the birds were used to, or did anything change (i.e. birds normally get...