The cats didn't catch it on their own, the scientist gave it to them. Makes a difference.
http://news.nationalgeographic.com/news/2004/09/0902_040902_birdflu.html
The researchers introduced the H5N1 virus into the airways of three cats. Three other cats were fed an infected chick. Finally, two cats were exposed to the virus by being placed in the same cage as the first three cats.
Here you are again misleading people.
From the article you linked to (maybe you didn't read it):
"The researchers introduced the H5N1 virus into the airways of three cats. Three other cats were fed an infected chick. Finally, two cats were exposed to the virus by being placed in the same cage as the first three cats."
Since all of the cats they mentioned were infected, cats can become infected simply by being around other infected cats. Does that mean, "the scientist gave it to them"?
In any event, three of the cats were infected by eating a sick bird. Maybe you don't have much experience with cats, but they tend to like to eat birds - even outside of laboratories.