Will Falconer, DVM Moderator
Thanks for stopping by, Ian. I'm glad you emphasize the outdoors with your boarders. That'll go a long way to prevent spread, should you get a flu dog in.
I've got a couple of kennels on bordetella nosode, a homeopathic protection without the downsides of vaccination, and it's been quite effective. Holler if you'd like more info. The vaccine for kennel cough is pretty worthless, according to those who've studied it closely.
And if you have any doubt of the harm possible from vaccines, just drop that word in the search box and read of few things I've posted over the years.
Happy trails.