In the literature I have read thus far, I have not come across the particular behavior that my birds seem to exhibit... and bare with me because I only have the slightest idea of how to describe this...
They are here on my desk with their food.. They've finished eating it seems and now there is a continuous mutual bobbing of the head at each other and very light squawking.. Nothing that seems to alarm me... Then they stand very near to each other and preen one another but then Apollo or Max will roll over while the other has a beak on his foot.

They are not making any fighting noises that I can tell and it all seems very gentle.. are they playing? Should this behavior be encouraged or stopped? I just don't think I've ever seen two birds together actually playing. Most of the babies in the nursery are usually sleeping or the ones old enough to be eating on their own are in separate cages.