I always seeing art of this character =3

Why does she hate on the canines?

Hunting dogs. Her entire herd/village was wiped out by hunters wanting the golden antlers her kind has. She was then chased to the point of starvation and nearly died. And it's only 99.99% of Canines, she was saved by Sam the Sheep dog and Ralph the wolf, if she learns that one doesn't pose a threat she's less mean and weary of him/her.

That must have been one hell of a meeting for those 3. So does just avoid them or does she think all canines are evil besides the ones she knows?

It was, considering Ralph found her half dead in the sheep flock he was trying to "hunt". He immediately got Sam's attention so he could help her out with some first aid. After her wounds were dressed Sam laid her down with some of his older ewes and Ralph kinda went easy on the "hunting" that day so Sam could stay close to her. When Hera woke up she was naturally surprised and frighted but when she saw how mellow the sheep were she calmed down enough to be taken care of. She avoids other canines when she can but it's mostly hunting dogs she thinks are evil. She hides behind her mouth most of the time, hurling snarky remarks and bitchy quips, and most of the time it works well enough for them to leave.