My staff Harvey (8) had a real shock when we bought Poppy (1) home last year. He's been an only dog all is life so did not take too kindly to this brash youngster ruining his life. They have had several spats as Poppy definitely wants to be top dog, but we have learnt very quickly to let Harvey deal with her - he doesnt hurt her, but he definitely lets her know hes boss. Plus we make the effort not to confuse Poppy, or put Harveys nose out of joint, by making sure that Harvey gets the treats/dinner first reinforcing his place in the pack. Although he is the boss he will also let her walk all over him at times ( I am sure its becuase he cant be bothered), but they seem to work it out pretty well between themselves.

Our dog jake is the boss although he will let pete take toys ect if he goes near his food there is a growl and pete knows.
We do the same always feed jake 1st and fuss him 1st

I give them treats at the same time and Bramble always wants what Archies got (even if they are exactly the same) and he would just give in and let her have it.

For the first time yesterday though, Archie approached Bramble (he'd finished his chew, she was still eating hers) and she really growled at him and, of course, Archie left her to it!