works in our house and weve got 5 lol...
but again we keep a close eye on weights and behaviour, no resource guarding, no overweight, good contion good energy...
it does realy depend on the dog and person in my opinion, many dogs just couldnt be free fed, others need only once a day, others need more others need less, im lucky, everyone gets along fine and noone tries to overeat and everyone gets enough...(obviously or theyd be loosing weight)
im very lucky also in the fact i get to spend MOST of my time with the dogs, so i know when they eat (in cases of emergencies) they come to work with me during the day and never leave my side when at home lol.