Hey Anne, I thought I would discuss this with you in a PM instead of appearing controversial in public. I was just wondering if you could possibly cite any sources about the hops only being bad if they are spent? Sorry, I am naturally skeptical because of the information I have been through other brewers. I would assume that if they were spent hops, they would be less likely to cause problems with dogs since the alpha acids have been boiled out into the beer. I know also that a lot of people say that they let their dogs drink light beers, but nothing that is exceptionally hoppy (Pale ales or IPA's) because of the high acidity levels.
I was also under the impression that hop pillows were generally made from stale hops that would normally not be suitable for brewing anything other than lambics, so the acids would fade away. I hope I am not sounding too stupid here... I am actually a fairly advanced brewer, but only recently started looking into adopting a dog. (I can't wait!)
-Weedy