behaviour

Question
I have a four month old Irish setter puppy (female) whose spent the last two months with me being protected from full grown golden retrievers who wanted to bully and play rough ! Because of the size difference initially, we kept a very close watch so that the puppy didn't hurt herself in play. Now that she's a litte larger, we let her join the game once in a while but she's very aggressive ! especially when it comes to the young male golden retriever (who was the biggest bully in the first place!) She snarls, snaps and her hackels go up when she's playing with him but is very gentel and loving towards him when they lie next to each other! is this play behavior agrression ? or is she just intimidated by him during play?
Sometimes, he inturn gets aggressive once she gets her hackels up. In this case who should be told off? the puppy or the grown up one?  

Answer
Sometimes it is tough to sort out what the dogs are doing.  Much of the play with young dogs is quite rough.  For example, see http://www.photolocker.net/images/Labman/gretchenandellaplaying.jpg  Notice the Lab's wrinkled up nose.  This is an example of fun playing.

On the other hand, when the hackles come up, it may be best for a time out, Everyone down and stay for a few minutes.  It is hard to sort out who first strayed over the line of reasonable play.  

Watch the 2 females.  As the Setter matures, she may challenge the Golden.  Depending on how strong willed the 2 are, you may or many not be able to enforce peace.