I had two MALE Yorkies, 2 years apart. No problem with them at all. They were the best of brothers.
In fact, they had the same parents.
When Spock, the puppy arrived, he was a typical puppy, trying to keep after his brother, Bumpy. No problem. Bumpy was much smaller than Spock but Spock learned to "respect his elder" most of the time. If Bumpy was at the food dish, Spock waited patiently for Bumpy to finish. As they got older, I did feed them separately so I could check how much each ate. They lived happily together until 14-year-old Spock passed away.
A year later, Bumpy joined him.
