the origins of the idiom not have a dog's chance : source !!!!!!thanks !!!
I need to know the origins of the idiom : not have a dog's chance
is there anyone who can explain the origin of the idiom ?
why does it mean " the poor ,least chance or a slim chance ?

Question

the origins of the idiom not have a dog's chance : source !!!!!!thanks !!!
I need to know the origins of the idiom : not have a dog's chance 
is there anyone who can explain the origin of the idiom ? 
why does it mean " the poor ,least chance or a slim chance ?

Answer

I have never heard this idiom before.
A simple dictionary lookup (http://www.merriam-webster.com/dictionary/dog's%20chance)
indicates it is the lower 10% of word popularity, so I would avoid using it.

This dictionary lookup gives this definition:      a bare chance in one's favor

I could not readily find any info on the origin of this phrase.

Normally, we say "You have a snowball's chance in Hell." 
(Hell is a hot and fiery place, so the snowball will melt extremely quickly and have NO chance of survival.)