Really nice post...
Not only is chemical pnemonia a problem in tight barns, but the stress of living in cramped tight quarters like you see in dairies, or in barns up north during the winter, brings on pastuerella. Pasturella is found the nose of every normal goat on the planet, like enteroxemia is found in the gut and staph on the skin, and worms in the gut and cocci...well you get it

Stress in the form of high humidity (like in enclosed trailer during shipping bring on shipping fever which is pasturella pnemonia) or high ammonia levels in the barn aggrevate the nasal passages and allow the pasturella with a break in immunity to flurish. Some goats with excellent immunity or perhaps they have been vaccinated will have nothing more than a runny nose (this was the curse of the southern show circuit two years ago) other goats with poor immunity will string snot, cough and die.
A really good trick is if you can kneel in your barn and don't smell ammonia, and when you stand up your knees are not wet, than your barn is fine. Ammonia smell and you need to vet your barn, wet knees and you need deeper bedding.
It hurts nothing to inject ivermectin to go after lungworms this far into pregnancy. But after that you need to deal with the barn issue, it's almost always that. Increase drainage, bedding and ventilation, an air tight barn always contains unhealthy stock. Vicki