toy and chewie possessiveness

Question
I have a 1 1/2 yr. old collie and an 11 1/2 yr. old collie, and 2 days ago I brought home a 12 week old collie puppy.  My senior dog does his best to ignore the puppy, and my 1 1/2 yr old female has been playful, except when it comes to chewies and toys.  She absolutely will not let the puppy (female) keep a chewie or toy.  When the puppy gets a chewie, she immediately steals it from her.  This will happen to each and every chewie available.  I have been scolding her when she steals the puppy's chewie, and she responds to me by backing off, but will go right back if I don't stop her.  I know it is natural for dogs to always want the other dog's chewie, but she is unrelenting with the new pup.  Is there anything in particular that I should be doing, taking into consideration that we are dealing with collies, and not some of the less sensitive breeds?  My 1 1/2 yr old, Olivia, has always been possessive with toys and chewies, as she took to stealing Ethan's toys right from his mouth.  Being considerably older, I am sure he didn't want to wrestle with her for the toy, although they have played well together using tugs.  I would appreciate advice specific to collies, as they are very sensitive and require handling of that nature.  Thank you.

Answer
Hi Karen;
Irish Setters and Shelties are overly sensitive too. You can't give them as severe a scolding as you would normally give to correct bad behavior.
You can't correct them too gently ot it doesn't have any effect.
You have to hit between a hars and a mild voice to scold with.
I would take the toy back, give it back to the puppy and tell her "no. you don't steal toys", and put her where she can't get at him to steal it again.
I use the small hall bathroom for a time-out place.
When she sees she doesn't get to keep the toy, and it gets her put in isolation for about half an hour when she does it, she will soon see it is in her best interest to leave the puppy's toy alone.
Just treat it like you would a human child that stole the other child's toy.
You do all the same corrections you do with any other dog, you just use a little milder voice in the corrections.
If you do not feel you are up to teaching it yourself, Man's Best Friend's trainers can probably do it in one class.
It is better, of course, if YOU handle the training as YOU are the alpha, and they need to know mom rules.
A good group obedience class will always help you.
Petsmart and Petco have group training classes on wekends, and the owner handles the dog and a trainer instructs the class.
VERY good experience for the dog AND the owner.
Charlotte