I leave for a little bit and I miss this great post about switching to raw! I'm weird, but I LOVE hearing about people going natural for their dogs! You've gotten some great advice here. I too, do the prey model raw. Pork is NOT a problem. I have two pigs in the barn now that will be killed tomorrow and going right to the dogs.
Re: gulping her food - you can feed big stuff, just take it away after she's eaten enough. Give her a whole chicken and let her work for a while, then put it in the fridge.
Re: the growing Pyr - how old is he? Growing dogs can need a LOT more than 2%, I usually do not limit them at all.
Re: fat - chickens will also appreciate any extra!
Re: why chicken to start, meats harder to digest - generally fattier meats are harder to start with, but if your dogs have had beef and pork and are fine, no need to omit them now. Also, those bones are harder, so some dogs need time to get gut in shape to handle them
Have fun with it!