Rarity: Oh dear. Are Fluttershy and Rainbow Dash… infected now?
DM: That depends on how well I roll over the next in-game day or so. But feather flu is like the normal flu: It incubates. On average, you don't show symptoms for 48 hours.
Fluttershy: So… we're fine?
DM: For now.
Rainbow Dash: Mmmnnrrrgh…
Applejack: The team's been trainin' together all week, and our hotshot's startin' to show symptoms…
Rainbow Dash: Arrrrrrrrgh…
DM: Feather flu, on top of being unpleasant, causes early molting in pegasi. When it's in full swing… they can still technically fly, but they really shouldn't.
Rainbow Dash: Ennnnnnhhhh…
Twilight Sparkle: If even a third of our team is exposed, we'll have trouble creating the tornado at all, much less breaking the record!
Rainbow Dash: Hrrrrrrrrnnnggg!
Pinkie Pie: Oh no! She's getting the feather flu in REAL LIFE!
Applejack: Nope, that's just her straining to censor herself.
Rainbow Dash: More like "trying NOT to punch the DM."