@Background Pony #2779
 
Celestia: “… and also scared the chicken” (talking about Luna)

GoBusters

@Midnox  
Cukoo confirmed.

Remember pony Link is canon? I think Celestia was REALLY good friend of a past incarnation of him

If only she had 11 mixed herbs and spices on hand.

@Dirty Bit  
Or having her arguing with Celestia, dismissing her chicken paranoia. Or on a funny note, having her coated in gravy…

@Magic Nova
 
Oh man, imagining an angry and ragged Luna wielding a butcher knife.

@Dirty Bit  
Someone gets it!
 
Celestia (After getting captured by the chickens alongside her sister): I told you they were organized!

@Background Pony #EA38  

 
Or deep fried in batter!
 
@Magic Nova
 
Chicken Run? XD

@Background Pony #EA38  
But chickens don’t want to become pies, especially since they don’t even like gravy!

@Magic Nova  

 
Chickens aren’t revolting, they’re great…especially with mashed potatoes & gravy! 😄

@Magic Nova
 
Now I remember that there were religious chickens in Pencil’s comic Anon’s Pie Adventure XD

Celestia: Luna, help me! The chickens are revolting!

I don’t speak Italian but I am now imagining her wearing a green hat and saying “oh no, it’s an angry cucco!”

I’ll bet Celestia fears chickens because she feels they’re unpredictable.

@Poptard  
If we’re counting IDW, Chrysalis.

Maybe half of the Royal Guards’ duties are checking the closets and under the bed for monsters and then stroking her mane to fall asleep. After all, she can’t win a fight and she knows it.

Somebody needs to save Celestia! Quick, call Colonel Sanders!

@Midnox  
That a hen.

@Midnox  
Kek

She’s afraid of cock. Lesbian horse confirmed

If you’ve played any Zelda game, you’d understand how powerful and dangerous chickens are :0

@Background Pony #6DA8  
She saw a chicken do horrible thing. Things from a lovecraftian nightmare.

@Background Pony #3770  
Because the villains have had anything but ease defeating Celestia before.
 
I think the writer’s have caught on and are running with that.
 
But seriously, Celestia’s (and Luna’s) powerful, but they don’t have the training and mindset to be warriors. Any foe they couldn’t best via their overwhelming power, they lost to or attempted to avoid/flea (the movie has them succumb to panic once one’s taken out and not think to flea until to late).
 
The chicken, I’d like to hear the story behind.

So she’s afraid of a Scootaloo?