A dog riddle is:

Q: Who do you stop a dog from barking in the back yard?
A: Put it in the front yard.

The riddle has been cited in print since at least 1983.

“How do you keep a dog from barking in your front yard?"/"Put him in your back yard” is the same riddle, but with the yards switched.

“How do you stop a dog howling in the back of a car?"/"Put him in the front” is a similar dog riddle.


Google Books
Rover’s Riddles
Yellow Springs, OH: Antioch Publishing Company
1983
Pg. ?:
How can you stop a dog from barking in the back yard?
Put it in the front yard.

11 November 1988, Wausau (WI) Daily Herald, “Just for Laughs,” Pennywhistle Press, pg. 6C, col. 4:
Question: How do you stop your dog from barking in the backyard?
Answer: Put him in the front yard.
Curt Burns Age 13
Newark, Delaware

Google Books
Nutty, Good, Clean Jokes for Kids
By Bob Phillips
Eugene, OR: Harvest House Publishers
1995
Pg. 161:
Abner: How can you stop a dog from barking in the backyard?
Abigail: Beats me.
Abner: Put him in the front yard.

December 1997, Children’s Digest (Indianapolis, IN), “Jokes & Riddles,” pg. 29, col. 2:
Question: How can you stop a dog from barking in the back yard?
Answer: Put it in the front yard!
Cami Hartman
Sumner, Iowa

21 October 2001, Sunday Telegraph (Surry Hills, New South Wales), “The Funday Telegraph” by Matthew Frilingos, pg. F1:
JOKES
How do you stop a dog barking in the backyard?
Put it in the front yard.

16 October 2005, The Sunday Mail (Brisbane, Australia), “Jokes,” pg. 106:
How do you stop a dog barking in your back yard?
Put him in your front yard!