So a farmer woke up early one morning and headed into town towards the market to buy a rooster, a hen, and a donkey.
The farmer got to the market and saw a nice handsome Rooster for sale. He asks the guy "How much for the rooster?"
"It's not a rooster, sir; it's a Cock."
The farmer says 'okay' and buys the rooster that's a cock.
He continues on and sees a beautiful chicken for sale.
"How much for the chicken?"
"It's not a chicken, Mister; it's a Pullet."
So the farmer makes the puchase and continues on with his rooster that's a cock, and his chicken that's a pullet.
He then lays eyes apon a sturdy looking Donkey.
"How much for your Donkey on this fine day?"
"It's not a Donkey, buddy; it's an Ass. And you need to know something about him if you are going to buy him. If he ever sits down, he aint gettin' up until you give him a good scratch under the chin."
"okay, sounds good, I'll take him."
So the Famrer is on his way home with his rooster that's a cock, his chicken that's a pullet, and his donkey that's an ass, when the Ass decides he would sit down and refuse to budge at the command of the Farmer. Remembering the advice of the guy at the market, he turns to a fellow farmer walking down the road and asks;
"excuse me sir, could you please hold my Cock and Pullet while I scratch my Ass?"
ba-dum, tss.