My 9-month-old Yorkie hasn't had her first heat. Is this normal?

Normally, bitches in season do not behave very differently from their usual selves. Since it is her first heat, there may be a problem showing up that was not evident before her reproductive organs became active. Or, it could be something else altogether. Your best bet is to take her to the vet for a thorough exam to determine an accurate diagnosis and, if necessary, appropriate treatment plan.

She could still go into heat at any time. Some dogs go into heat later than others, although smaller breed dogs tend to go into heat by a year of age. It could also be that she has gone into heat, but it was a silent heat so you didn't notice any signs of it. I'd have her checked out by a vet to be safe. Best of luck.

She may be extremely clean and you might not notice when she is in heat. If you intend to breed her I suggest you have her examined by a theriogenologist or veterinarian specialised in dog breeding . She may not be cycling due to ovarian cysts, or may be missing ovaries, or have hormonal problems.

You are correct that Panda could start going into heat suddenly, as female dogs can start their first heat any time after six months. If you don't bland on mating Panda, I would get her spayed as soon as possible.

This is normal. Dogs have can silent heats where they go into heat but show no signs of it. They can also heats where they don't bleed as much. This does not require a vet visit. I hope this helps!

Yes, this is normal. Sometimes a dog's heat is more subtle than others, and that can happen considering it's her first heat. It is never recommended to breed a dog on their first heat, so I would keep Toi away from your male dog until her heat has passed.

I'm wondering if you mean that Belle has an underbite. This can be common in breeds such as the Shih Tzu. As for not being in heat yet, she can go into heat anytime, so I would not worry about her being nine months and not having a heat yet. It can take up to a year of age before she goes into heat. I wouldn't be worried that there is a problem with her reproductive system. Best of luck, I hope this helps!