[Ellie May]

I would not go without it.
I'm not sure when you're leaving but you can give it about 25 days before you leave so if they get sick it will be at home.

If these were big dogs I'd recommend Heartgard because of the low reaction rate but some Yorkies do better with Interceptor. Either one is fine though. There is no need to use Heartgard Plus (unless you want to) because there is an extra ingredient in it for intestinal parasites which your dogs don't need and it's another chemical for their bodies to deal with...