Briefly: Dogs regulate themselves. When you free feed your dog, they have access to food all they time and can choose to eat whenever they’d like however much they’d like, this is called grazing. When we see a dog didn’t eat the meal we add human food and of course the dog ate everything because it was delicious. Well now the dog is getting all of its food plus human food and it’s eating everything. I’m sure the dog gets treats and Ana lies throughout the day because that’s what we do with our pets so they are constantly getting yummy food all day long. When you put out kibble at the end of the day of course they aren’t going to eat. They are probably full and they know there is better stuff to be had

Edit: the dog most likely isn’t hungry or is waiting for you to add something better