
Anything that was to be eaten as opposed to recreational they got in their dishes and knew not to touch the others if they finished first. I would then make anyone who had finished leave the kitchen until the others had finished theirs. I have always supervised meal times until they know that taking interest in another's food bowl is not allowed, and continue to hover so they know I am watching, even i in the next room :D
With recreational bones they all share. I always make sure there are more bones than dogs and never have a problem.
The dead bones (empty and well chewed remains of marrow bones) are available all the time anyway until they are too small and then get binned.
For this reason I don't think they consider them high value, as they will share equally happily with canine visitors. The interesting thing is that canine visitors that would squabble about bones at home don't when they are with mine?
I think you need to get the dogs used to being fed near each other in the knowledge that no-one will be allowed to take their food, and then they will relax, but I suppose ti depends on the dogs characters.