Jessica,
Your post seems to address several issues: food training, a sudden lack of response on OB, and a question on using corrections.
I wasn't going to jump in since everyone was already saying what I would have said, but it sounds like you have a similar problem to one I had: an OB issue with a slow maturing dog, who has natural high aggression but relatively low prey drive. (That is, low prey relative to the high prey sch dogs you normally see at clubs.)
I can't walk in your shoes, but I can tell you what worked for me, if you will bear with a long post.... <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
First: training with food -
My bitch (WG/DDR-Czech) has fairly low prey drive, and high food drive. But like you, I don't want to keep feeding her during training, not only because she gains weight easily, but also because I've been advised that dogs retain their energy/drive longer for the anticipation of getting a toy, than for getting food. Certainly such is the case with my dog.
Now...she will retrieve a ball/kong, but unlike our WG dog, who retrieves for the chase, I found that this bitch retrieves for the fight (tug). Only if I am willing to fight her for the item does she consider it worth while to chase it down. Ie, she "comes up" in drive during a tugging session, but not for prey chasing/retrieving.
I wonder if you may have the same issue: low prey evidenced by lack of interest in chasing. So how about switching to a tug item? No chasing games, but rather tug games. The tug item may then become of enough interest to her that you can use *it* instead of food for training. You will have to build her interest in the toy by playing tug games...and she's going to look funny at your strange behavior the first couple of times, until she gets into the game. Just let her pull you around with that toy. To play this game, she must know the out/give command, otherwise you will need to use two toys/balls. (I use a ball on a string, as the dog shreds the jute tugs!)
Second: sudden reluctance for Ob -
I have experienced this with my dog: she learned all the ob commands, and about the time I thought we had things down pat (even passed the BH), decided not to obey anymore! Lagging on heeling, refusing to retrieve a dumbbell, just generally giving me the message to "Buzz off!". I wonder now if that was a delayed "teenage" phase in the dog, which I experienced with the faster maturing WG dog at about 9 months. My reaction to that ob reluctance, in retrospect, should have been to lay off heavy training, and just do more play for a few months. Unfortunately I didn't do that...
Third:
motivations -
I firmly believe NO dog works for nothing: there has got to be a payoff for the dog, just like in the wild...a satisfaction of some drive: prey, food, pack/social, aggression, etc. Most AKC OB classes use food/pack drive combined with aversive corrections. Most dogs will learn to perform very correctly but not in drive and thus without much enthusiasm.
#1 Learning Principal: Behavior not rewarded will soon go extinct. If you don't reward behaviors then you're left with aversive methods, which you already found out your dog won't accept without an unwanted reaction.
(Of course you can get into a "I'm the boss!" macho-mode, but convincing the dog you can mete out punishment better than she can does not address motivational learning. In fact, you will be using aversive learning methods at that point.)
corrections -
I've not had the problem of my dog coming up the leash at me for a correction...but then unlike you, I've had this dog in the house since 8 weeks old, and she is subordinate to an older dominant male dog who also lives in the house. I do have a dog that doesn't take corrections (from me). Because she has a high pack drive, her reaction is not to attack me, but to avoid (passive-resistant in human terms). The results are the same: a dog that won't do as you command.
Unfortunately I took the advice of a schutzhund trainer (who himself has a very hard, prey monster of a dog) and did not go with my gut feeling. Big mistake.
Being slow maturing, the dog was too young at the time for the type of corrections he taught (Force her heel with attention! Put the heat to her! Use that prong and correct her through the avoidence! Ignore those yelps! She's just trying to fool you!")
The result of his advice, and my following it, is about a year lost in training. I learned the hard way that with a handler sensitive dog, (and John mentioned earlier, this may be the case with your dog) relationship is everything. You got that, and the dog will go through fire for you! So like John advised you already, I then laid off any OB for many months and just played. Did tracking and protection, which were never a problem, but no OB.
After several months, and the dog just turned 3 yrs old, I am back teaching attention heeling. All toy motivated, but toy-tugging, not toy-prey! Short intense training sessions with OB commands interspersed with very physical tug play. And what a difference! A dog in high drive will take necessary corrections (voice is enough with this dog) without turning a hair. And instead of a dog that walked away when she saw the prong collar in my hand, she is now coming to me to work, jumping around and anxious to get going!
So be patient. Unfortunately AKC classes reward the youngest dog title accomplishments...which is not very wise. What I learned from my experience is:
--Let the dog mature and you will accomplish much more, with far less problems.
--Use the time to build relationship and drive through lots of play. Use that play time to teach the ob exercises.
--Ask advice of a breeder of the DDR lines: these dogs generally do have a consistently different temperament! My experience is with a dog only 1/2 DDR (though she seems to fit the model 90%) and I really didn't feel I was getting anywhere until such a breeder gave me some training advice. Yours with 100% DDR lines should be more predictable.
Good luck!