Basic obedience food training is one of the best ways to get your dog to understand what you are asking of him. It also cements that you are pack leader, as you are controlling the food. This film shows the dogs waiting for their food and then being called in one by one and told to sit before being given the go ahead to eat the food. I would not normally suggest that you do all your dogs at the same time as this can cause them confusion. Start with them individually.
If the dog does move, place them back on the same spot where you first asked them to sit. If you don’t they will think they can ‘creep’ and get away with it.
I like to only give a command when the dog is looking at me (where possible) this will encourage them to focus on you and hopefully not be distracted.
Once they have finished their food, do not allow them to ‘swap’, quietly sit them up and wait until the others have finished. I then gather in the bowels. I don’t like my dogs to be too active after food so I will give them 20 mins or so of ‘down time’ in the kennel or crate. Playing vigorously after eating or unning, jumping and especially rolling over after eating increases the risk of stomach twist. A leisurely walk around the neighborhood is fine and may aid digestion, but more active exercise should be restricted for one hour before and two hours after eating.