First I would like to thank the team for this excellent game and I was wondering that why can't there be a default band of workers programmed to pick food from the farm connected to the corresponding city/town and only if walls are needed to be built or mines worked upon then extra ones can be created but ofcourse in the game play you do get slaves
Generally, you only need to use workers to carry food in very specific cases. Most of the time, just connecting your farm to a city with a road is sufficient. And don't forget that you can adjust the stockpile level on your cities if you need to.