IMO.......
as peter piper had been pickin peppers a long time, he would be tired from the journey, and pretty sick of pepper pickin.....and....if what u are sayin is true bout jack and jill bein employed for this very reason, then i would say, jack and jill went up the hill, to fetch some pickled peppers......
which (by the way) would mean that jack and jills heads would b slgithly towrds the pickled side aka - slightly wrong, and they would therefore not pick enough of the ripest peppers.
this is why they need to take along the firkin to assure the correct density and ri[peness of pickledness is observed......
but.....when u get to the land of the peppers......u will me the lord of pickles, and he demands a toll for the picking of his pickled peppers (it takes a lot of effort to pickle them) and he demands 34 firkin feathers for his dues - one of these must b the gold feather from the firkins left ear socket.......
and since he is the lord of pickles, aka, the lord of wrong, he is always fekked and u can get away wit it......so i reckon, judgin by that theory....a firkin has 34 feathers, unless the lord of pickles suddenly becomes peppered and jack and jill go up the hill to pickle peter piper.