Weight ranges & lifespan
Toy-sized dogs mature fastest, & dogs under 10# are full-grown at 9-MO.
That said, no dog should be bred B4 they're 2-YO, for 2 reasons -
* 85% of heritable problems will be symptomatic / visible by 2-YO
* waiting to mate for the 1st time till they're 2-YO adds an...