When Penny tells Bolt to "zoom-zoom" as they're fleeing the fire, Penny coughs uncontrollably while Bolt seems unaffected. Smoke rises, and Penny's much taller than Bolt, so is inhaling much more of it.
While at first the opening scene seems typical or even trite—of course Bolt, the one dog that's visibly different, is also the only one behaving differently from the other puppies and also somehow the only one that notices and is interested in greeting a young Penny, he's the protagonist. It actually makes sense, though—the other puppies appear to be both younger and of a softer, calmer, more companionate breed, and they're focused on the shelter worker because he has their breakfast. Bolt, on the other hand, has the classic build of a white-morph German Shepherd mix—an intelligent, energetic, high-drive breed that needs a lot more than just kibble to motivate them. He's not ignoring the shelter worker because he's Special And Unique; he's ignoring the shelter worker because he's bored, and much more interested in the interesting novel stimulus of a new person than in his breakfast.
Bolt doesn't have super powers, but pretends that he does because he believes he does. Mittens doesn't have claws, but pretends that she does because she knows she doesn't, but that's all she's got. Think about it. So similar, and yet different...
This movie has lots of it, but the in-universe studio takes the cake. Its Enforced Method Acting is deceptive, manipulative, and evidently places a huge burden of emotional distress on Bolt, even before he escapes while still thinking he has super powers. Given that this is all done merely to make his performance seem more convincing, it borders on animal abuse. And then there's the ridiculously unsafe set design; torches that use real fire (instead of the fake fire they use at some restaurants) surrounding a pad below a little girl who's literally tied up? Even if they didn't expect the dog to end up knocking over the torches, they couldn't be certain the torches WOULDN'T get knocked over, making it still indefensibly unsafe. Either the set designers Didn't Think This Through, or they thought having slightly more convincing fire was worth risking the life of a little girl over.
To top it all off the movie ends without resolving any of this. Bolt is still airing and it's never suggested that our antagonists are fired or learn anything. This is bad news for the new dog/girl hire.
Arguably, they very well could have replaced the entire production staff (and given the network exec's threats at the beginning, it's very possible), which would explain the show taking such a drastic turn of direction.
Really, Bolt was a danger to himself and others when he thought the show was real. He could easily have been killed many times when he tried to jump over things, stood in front of cars expecting not to get hurt and jumped out of trucks. He also thought all cats were evil and thought nothing of holding Mittens above a road full of cars to get information.