The obvious, from the word order, (it's not a barny fart, so not a fart that's like a barn), it's when a barn itself farts.

Could be a fart so strong that it rattles like the doors on a barn in a storm? Think the film Twister.

ALRIGHT, WHO LET THOSE TWO COLLUDE AND PONTIFICATE?! WHO ALLOWED THAT TO HAPPEN??? GO ON, STEP FORWARD OR WE'LL BE FORCED TO PUNISH THE BLOODY LOT OF YOU!

What happened to "Porto"?

Actually, I think my problem is that I rather enjoy thinking about the ramifications of phrases like 'barn fart'

barn fart

I wish I could say this sort of thing doesn't happen to me, but that would be a lie.

The barn probably got the farts from all that dairy

I don't care how it happens but I want Emily and Hanners to have babies.

Now I can't get the image of a bat in a microwave out of my head.

Did it work?

I'm not the only person who wondered what would give a barn the farts, am I?