The definition and abbreviation for Potentially Hazardous Food (Time/Temperature Control for Safety Food) or PHF/TCS should be modified to drop the reference to potentially hazardous food and PHF.
Yes, as a treat apples are fine for chickens. Some will say it is best not to feed them too many apples as the seed of an apple has a small amount of arsenic in it. I have an orchard on my property and in the fall, the chickens run there first thing in the morning. Never had a chicken drop dead under an apple tree.
Select fruits, vegetables and grains will keep chickens happy and ensure they are receiving a nutritionally balanced diet. Good choices include leafy greens, cooked beans, corn, non-sugary cereals and grains, berries, apples and most other fruits and vegetables.