Maybe they stuff the pigeon with the mice?
Seriously I guess vegetarian geese weren't fed the usual stuff. You know how cows are supposed to be vegetarians too, right? In the past they were sometims fed grain with offal mixed in, in fact becoming somewhat cannibalistic.
I laugh when I see adverts for "Grain-fed western beef". Cattle aren't supposed to eat grain in the first place, they can't digest it, which is why we have to shoot them full of drugs and hormones.
Cattle should eat grass.
And geese should eat...whatever it is they eat.
Yes, BSE (mad cow disease) was originally caused by cattle eating beef (ground-up bits). A prion-disease in New Guinea, kuru, was caused by the consumption of human brain.
The vegetarian goose is made from braised tofu. Miced squab is most likely minced squid -- but I'm not going to find out!
"which is why we have to shoot them full of drugs and hormones."
No you don't. Lazy slack assed farmers who don't give a toss about their customers use drugs and hormones. Give these suppliers a wide berth as they don't deserve your hard earned money. Search out real food suppliers. Yes it takes a bit of effort but heck it's worth it. Remember you only live once my friends