“Why did the piglets do badly in school?”/“They were all slow loiners.”

A piglet riddle is:
 
Q: Why did the piglets do badly in school?
A: They were all slow loiners.
 
The “loiners”/“learners” pun was posted on Twitter on December 14, 2009.
 
     
Twitter
Phyllis King
@PhyllisKing
Why did the piglets do badly in school? They were all slow loiners.
1:46 AM - 14 Dec 2009
 
Twitter
Eric Ahn
@Eric_Ahn
Why did the piglets do badly in school? They were all slow loiners.
8:53 AM - 20 Dec 2009
   
Google Books
Sensible Nonsense.. Frank’s Comic Pack:
Humour Pack Series
By Frank Paul
BookBaby
2014
Pg. ?:
Why did the piglets do badly in school? They were all slow loiners.
   
Twitter
Sephora Offers
@JoshuaBoycie
Why did the piglets do badly in school? They were all slow loiners.  yes
8:48 AM - 19 Feb 2018
 
Twitter
Lucky Score
@LuckyScoreNet
Why did the piglets do badly in
school?
They were all slow loiners.
#Joke from #PigJokes in #Jokes, #Humor and #Satire
11:08 PM - 10 Apr 2018