Some things are easier to find than others.
I find it much easier to imagine farting into a hay stack than be doing some important darning near one. I might have visited the hay stack to do my farts so that no one elsewhere smelled them, or I might have been stuck really high up on one and farted and so nestled into the hay to deliver it carefully. I can't imagine any reasons why I'd be mending cloth on a hay stack, it'd take a really big life diversion to make that happen. Hay is soft there's no way you could have ripped your clothes on the way up to the top, unless your clothes are made of gossamer, in which case I don't think your average needle is the right implement for mending.
You'd probably need a spider or a silk worm or something.
If the spider or the silk worm farted, now that would be harder to see in the hay stack. But I'm not even sure they fart - I don't have much idea about the digestive systems of insects. Hay stacks are my area of expertise, hay stacks and things that can and can not be easily found in them.
Thanks to my copious amounts of free time today I've really been able to give this area a lot of thought and I have made big break throughs. I believe by the time this publishes I'll be neck and neck with Putin for the big one.