I've known about Iams links with animal testing for some time (and also Eukanuba, made by the same company). Have never used either brand.
Hope you know that you're opening a large can of worms. Iams and Eukanuba are made by Proctor and Gamble who have been involved with vivisection for many years and refuse to stop. The company and products are regularly highlighted by PETA and the like. Many don't realise the extent of their brand ownership though. They are very hard to avoid. Personal and household brands include:
Very interesting! I knew about Iams and some of the other products mentioned, but it's great to have a comprehensive list! We've been boycotting P & G products for years, but our list was out of date!