Treat Protectiveness in Puppies - A Case of Food Aggression? Part I

In almost all respects our puppy Charlie has been everything we ever expected. So when we began giving him these wonderful 100% pure chicken strips last week and he became very protective of it, we were thrown for a loop. A friend of mine, who I am sharing alot of pup experiences with (as she has her own new pup), came for a play and brought Charlie one of these new strips to try. He adored it and so we purchased a bag the next day. When he was given the new treat, his behaviour or body language seemed to change. He showed an almost "every man for himself" type of look. He took the treat and ran to a protective place, behind a chair. I initially thought it was cute that Charlie was so in love with his new treat and that he likely wanted to enjoy his "pleasure" by himself. It wasn't until my son had to crate Charlie, who happened to be eating his treat at the time, showed some protectiveness of the treat by giving a growl. Unusual, because we have practised since the beginning to have someone (whether one of the kids or my husband or I) sit for short periods of time with Charlie while he ate to get him comfortable with us around his food so he would know that there was no threat to his food. So, the protectivenss (growl) with the treat was surprising. I hate to use the word aggressiveness as I tend to think a growl shows protectiveness and a bite shows aggressiveness (if this is not the appropriate language in the canine behavioural world, please excuse the faux pas). When my son reached to take Charlie out from under the table, he growled. My son looked at me in dismay as if to say "where's Charlie?". What had happened to our playful, fun loving little furball? I didn't know what to think. So, as usual I began to source out the driving force behind this behaviour. After consulting a number of sources, I am now satisfied that Charlie doesn't have a "Jekyll and Hyde" personality, but he is simply canine. My best answers indicate that Charlie is canine and his behaviour is canine and instinctual  and it is our task as responsible pet owners, who want to harmoniously live with our dog, to teach Charlie that when his pack leaders (whether my son, me or anyone else in our home) make a request of him that he must give up his treat or whatever else he is doing, as he is and always will be the "lowest on our pack pole". I have resolved that the best course of action would be to purposefully begin to train him to give up what is his when he is asked. We will first reward a behaviour by giving him a chicken strip. After a few minutes I will have my son, armed with a highly favoured liver snap, approach Charlie and ask him to "give" the treat. From here on end we'll use the word "give" as the command word for Charlie to give up whatever he has at the time. After two times with the word "give", I will then have him offer the liver snap in exchange for the strip. Once the strip is delivered he will praise him for giving and Charlie will be given back the strip. We will repeat two more times and then let him enjoy his treat. We will continue to practise this method of giving up for the next few days until Charlie gives up his treat on command and with no exchange of treats. We'll have everyone in our pack practise this exchange with Charlie to help reinforce that all in our household are higher in status than Charlie and that he must surrender all that is his on demand. Our goal is that Charlie will learn and know that he must always give up what he believes is his when asked by somebody else in his pack. We will keep you posted on our success.