Clearly its because of the suit. Hasn’t she heard that quote from Mermaid man?
 
“why else do you think we run around in colored undies?”

And then the egg hatched, revealing a little foal named Screwball. Pinkie raised the infant, who grew to a full-grown mare within hours. Screwy then got her cutie mark in a baseball game with the Mane Six (which drove all of them save Pinkie insane). Then, Screwball told her mother Pinkie that she would have to go, and take their memories of her with her. She would go learn to control her chaotic powers, prevent ponies from going crazy around her. Pinkie broke down into tears, afraid to forget the daughter she never thought she’d have. Screwball hugged her mother, singing into Pinkie’s ear: “You~ are my Mommy Pinkie~ and I~ am a piece of you~”  
With that, Pinkie was the only one to recall Screwball, but she concealed her bereavement. One day, Screwy Pie would come home, and be with her mother.

Pinkie, it’s chocolate

And they re-used the vector they first used for Spike’s egg…
 
That just raises more questions.

they do when im around, pinkie ;3

@DanielTepesKraus  
Exactly what I was thinking.

Dat is a seriously cute face.
 
How long until someone ruins it with a chickun-faced Scootaloo hatching from it?

whyboner.jpg

@Background Pony #A95D  
Well Pokémon couldn’t show 10 year old kids the birthing of mammal Pokémon.

In Pokémon they do.

I’m pretty sure not all eggs are fertile.