Long time ago i put a average 27" track greyhound dog over a 23" border collie bitch that refused to work the woolly backs .
I lost the top of my finger in the process as the greyhound bit it off lol
Kept 2 bitches and worked them on Rabbits, Hare, Fox.
They were a bit like chalk and cheese but did very well.
I cried like a baby when they died.