not like this is true or anything.. but I once was told (like 20 years ago).. that feeding meat instead of kibble would make your dog bigger besides healthier... well.. my first dog I fed meat... and now I believe had to do with genes but back then I was only 10 ().. so I believed it when I saw my dog grew bigger than most her breed about 2in taller (not that much but still)... then I realized it was just genetics...

although food might have a play here... as you can see why some people tend to be bigger, slimmer, smaller, etc.. and most is because the food they get...(not getting into healthy issues)...

as well as the runt might be smaller.. I´ve seen/had runts that grew just the same or even bigger than the bigger sibling...so it´s a complicated thing...

some guys are just small because they are that way and some are small because of the nourishment they took while growing... bottlefed or not they could just gain up later in life, I mean they were not bottle fed for a year, in which most growing occurs.. so if he was bottlefed for lets say 30 days then well fed for the rest of the year (which I´m sure he was/is) I think he´s just small because that´s how he is...

the building muscle is a great idea for making him as mentioned more "durable"... but I see no problem with Dora... she might be slightly bigger than him, but I see no prob at all... just like Ashlee said... look at Kyra and Jack/Shadow... or Chopper and Champ/Duke....