The phrase "free feeding" refers to the practice of leaving food out all the time for pets to eat whenever they want, rather than feeding them at specific meal times. Full definition
Don't free feed your dog as most dogs will eat until the bowl is empty. (dogingtonpost.com)
Instead of free feeding or feeding only two meals a day, divide the food up into smaller portions and increase the number of meals fed each day. (thecatcoach.com)
This means that food is left in the bowl at all times for free feeding. (thedrakecenter.com)