“What do you call a mischievous egg?”/“A practical yolker.”

An egg riddle is:
 
Q: What do you call a mischievous egg?
A: A practical yolker.
 
The joke was cited in Boys’ Life magazine in February 1983 and is frequently grouped with Easter egg jokes.
 
   
Google Books
February 1983, Boys’ Life, “Think & Grin,” pg. 74, col. 1:
McMuffin: What do you call a mischievous egg?
Humpty Dumpty: A practical yolker .—Chad Shryock, Sullivan, Ind.
 
6 August 1996, Chicago (IL) Tribune, Kidnews, sec. 7, pg. 9. col. 3:
What would you call a mischievous egg?
A practical yolker.
 
Google Books
Big Bad Classroom Jokes
By Sandy Ransford
London: Robinson Children’s Books
1998
Pg. ?:
What do you call a mischievous egg?
A practical yolker.
   
14 April 2001, Evening Mail (Birmingham, UK), “Chipper Club: It’s A Yolk!,” pg. 32:
What’s another name for a mischievous egg?
A practical yolker!
 
Twitter
Tony Letts‏
@TonyLetts
Anyone got any egg jokes? I’ll start you off - What do you call a naughty egg? ..A practical yolker
6:05 AM - 12 Apr 2009
 
Twitter
Maria Lawlor‏
@marialolza
What do you call a mischievous egg? A practical yolker! Not funny.
6:14 AM - 8 Dec 2009
 
Google Books
Funny Easter Jokes For Kids
By Peter Crumpton
PeteyRF Creative
2015
Pg. ?:
What do you call a mischievous egg?
A practical yolker.
 
Google Books
Katie Woo’s Hilarious Holiday Jokes
By Fran Manushkin
North Mankato, MN: Picture Window Books
2017
Pg. 9:
What do you call a funny Easter egg?
A practical YOLKER!
   
LondonlovesBusiness
These are the funniest Easter jokes
10 April 2017 | By Chloé Western
(...)
6. What do you call a mischievous egg? A practical yolker.