@Daneasaur  
Im not sure what Ember had to do with this but that is indeed what runt typically means.  
However, it also gets often used for name-calling when reffering to a younger, and thus smaller, kid. In common speech, it just reffers to someone smaller in a group, without implying the size is a birth defect or condition.
 
Also, I’m confused. Don’t birds also have nictitating lenses to protect their eyes while flying fast? When did that became synonymous with ground-dwelling creatures? About his personality, well, he also lacks almost every single impulse dragons seem to naturally have aside from greed (competitiveness, aggressiveness or independence) which suggests most of these things come from upbrining rather than instinct. Maybe they also don’t have this pining until their wings grow.
 
I don’t know, its all conjecture of course but I just don’t think there’s enough evidence to confirm he won’t grow them. The fact that we’ve never seen another dragon his size/age with wings, is also part of it.

@Background Pony #8DEB  
The only other comment made by anyone was Ember, who called Spike a Runt.
 
Runts of a litter often lack the growth, health, and ability to survive like other members of the same litter. If what she said wasn’t just an insult/statement to remove Spike from the contest, then Spike may indeed have been the runt of a clutch and, as part of his lack of health, may have been born without limbs.
 
That said, I’m not so sure Spike is of the flying dragons and is actually an earthdrake, resulting in more strength and durability than a flying dragon of the same size. It would explain his nictitating lenses, his skill at digging, and the lack of any pining to fly.

@Daneasaur  
Well, neither was exactly “natural” so there’s that.  
One time he was just “gigantified” by Twilight, and the other one seemed out of control. I believe Zecora even used the word “monster” to describe what he was becoming. I guess there is room for debate about whether any of those is anything close to what he could look like growing up the normal way.

@Background Pony #8DEB  
I just mean it’s silly since he’s “grown up” twice and neither time has he sprouted wings.

@Daneasaur  
He’s a dragon and 99% of the dragons in stories/shows/games/etc have wings, so people like to think he’ll grow wings.  
I don’t think its that complicated.

@Blissey1  
I mean, I am not saying you can’t do what you want in your own images, I just personally don’t understand the reasoning.

Super Pregnancy Force, Go! X3

@Daneasaur  
maybe they just like the idea of spike having wings

My only criticism is, once again, Spike has wings for some reason.

Only criticism I have is that there’s nothing in here to show that this is macro. They could just be resting together in a normal-sized crag.

I approve of this