It’s an old phrase from back when most dogs did work. They were normally farm or hunting animals and worked all day everyday for little reward!
That is not why that is said here in the US. It’s lazy folks who say that because they really don’t want to work. They want a simple easy job which requires the bare minimum thanks for sharing Cheryl
It will still be where the saying originated from.
You are probably right Cheryl. It makes sense. I have not heard this expression in my life