Sorry I'm several weeks behind on the FML so if someone suggested this, I
apologize.
 
Tell her to get a carbon monoxide tester or you buy it for her.  They
only cost about $10 at Home Depot and are well worth the money.  Put it
in the ferrets' room and monitor the air quality.  Or keep their windows
wide open all the time to let the gas vent.  It is deadly, deadly, deadly.
Then have someone come look at the furnace or boiler to make sure it is
operating properly, same with all other appliances.
 
This is a human health risk for her too, so if she doesn't do it for the
ferrets she should do it for herself before she becomes very, very ill,
or has mental health issues due to the influence of the gas, or she dies.
 
The fact that the house has little critters keeling over should be a HUGE
RED FLAG that something is wrong in the environment that likely will kill
or injure humans eventually.
 
Hope this helps,
 
Ann Barzda
Hillcrest Ferrets
[Posted in FML issue 3789]