The most interesting inferences come from the statement of Tolkien - "Bolg son of Azog." A fairly innocuous statement at first glance, but it has powerful inferences on orc life. The two cheiftains of the Misty Mountain Orcs are father and son. This means that Bolg could make a statement that he was reasonably certain of his paternity. Furthermore he seems to have taken a family feud with the Dwarves across a generation. This implies that orc cheiftains, at least, had unique access to certain orc females, and these females either refused mating with other orcs or were prevented from doing so. It also suggests that pride in ancestry was not unknown amongst orcs, and possibly that orcs felt some level of duty to relatives, enough to believe in keeping up an ancestral enmity at least. This also has implications on orcish hierarchies. I wouldn't suggest that Bolg succeeded his father in a regular fashon, like in European monarchies, but it suggests that rule of the strongest was not the only factor in orcish leadership.

To me these factors tend to suggest that orc females were kept in harem-like conditions. This would have a number of benefits for the leaders in orc societies. They would have access to the most desirable females (whatever that would be to an orc - nice fangs perhaps), they would be sure of paternity, and having the power to grant breeding opportunities would give them a powerful means of exerting control over, and rewarding, loyal followers. If orc females were kept in seclusion this would also account for their lack of visibility in Tolkien's stories. Bolg had a bodyguard of particularly large fearsome orcs, who seemingly discharged their duties with a high degree of loyalty - perhaps sealed by their reward of enhanced breeding opportunities as well as access to the best food and booty.

Orcs seem to have been capable of courage, though this was greatly enhanced both by the likelyhood of success in battle, and the control or threat of a master figure. Orcish valour is seen on numerous occasions in LOTR - the orc cheiftain in the Chamber of Marzabul, or the repeted uruk attacks at The Hornburg for example.

Orcs seem to have been very clannish and distainful of other branches of their own kind. This seems to hold true for both free-living orcs and those in the keep of masters. Note the fight between the two factions of Sauron's orcs in the Tower of Kirith Ungol.

Most of what I've said applies to free-living orcs, those in the service of a master would exist under slightly different conditions. It is evident that Sauron and Saruman had selective breeding programmes for their orcs, which is how they "Bred" the modified orcs the Uruk-hai. If I am correct about the harem status of orc females this would allow selective breeding with little interference with how orcs would behave if left to their own devices. Thus Sauron would keep the most favourable orc females and only allow those orc males with the desired characteristics: size, strength, ferocity, courage and cunning, to mate. This would also work as a form of control and reward for faithful service as outlined above. As conscientious breeders Sauron's stud managers would have to keep careful note of lineages and and paternities. This would also have the side effect of allowing the orcs so bred to have a pride in their ancestry which would help in inculcating the spirit neccessary for effective fighters.

The word "Snaga" meaning slave was used by an uruk of another breed of Mordor orc. This may imply that slavery existed in orc society. In free orc society, given their clannishness it is easy to envisage captives from a foreign tribe being reduced to a slave status. However, how the snaga orc was more of a slave of Sauron than the uruk is difficult to say.

Hope this has given a little food for thought.