Feeding stray cats

Question

Rabbi, my roommate decided to start feeding stray cats that roam our back yard. When she began feeding them, I asked her not to because, well, they are strays, there are at least 7 of them, and I did not want pets. She went ahead and now feeds them daily. I remain opposed in principle but it is her choice to feed them if she likes and they aren't allowed in the house. My roommate has asked me to chip in with the cost of catfood and I have refused to do so. I also refuse to feed them when she is away and ask her to arrange for others to do so. I have been called cruel, heartless, a cat-hater, and all sorts for not wanting to deal with these cats. My question is, what is the halachic status of my roommate's relationship to these cats, and what are the implications for me? ie does she have a chiyuv to continually feed them? Are they her cats? Can she eat before feeding them? Does she have to make arrangements to have them fed if she goes away? Should she not go away if there is no one to feed them? If they are sick, does she have to tend to them? And by extension, if they are now halachically her cats, would that in any way oblige me to take care of them? Right now, she only feeds them and nothing else. This has been for around 2 months now. Thank you