Tigers of my acquaintance go crazy for horse meat, especially when it's slightly gamey (starting to go off). Some will turn their nose up at rabbit. Interestingly, a keeper I used to know acquired the carcass of an Indian deer species for tigers to eat (thinking they would really go for it, being natural prey) but they didn't like it at all - typical cats!
Chicken & rabbit seem more likely than horse to give bacterial infections / food poisoning from what I gather (not really my area).
I wouldn't have thought bacterial infections were a huge concern considering the strong stomach acid and anti-microbial properties of the saliva. I certainly have never heard of any problems with chicken!
However all rabbits I've ever fed have been gutted to prevent the cats contracting liver fluke, and I've heard that there are particularly nasty viruses and parasites that could be contracted from pork (yet another reason not to feed it).
It is completely true that every individual has different tastes and the contrary nature of cats is one of the joys of working with them and why they should always be viewed as individuals I've known litter brothers where one will eat mutton/calf/pretty much anything and the other will only eat horse! Fussy devil!
As for separation I know one keeper who will never separate unless absolutely necessary and another who sees it as an essential management tool.
Reasons for separation are usually for medicating, ensuring each individual receives the correct amount of food, reducing risk of fighting over food, preventing breeding when not recommended (the female Amur at Howletts has an implant), and reducing the potential risk of the male when the female is pregnant/has very young cubs. The perceived risk is not always male aggression but sometimes that the female may view him as a threat and so separating him can reduce her stress.
This is not always true of course, and sometimes separation is an even greater stress, as in with Clouded leopards.
