Assuming you are serious (please excuse me for wondering, but it's the strangest post I've seen in a long time): Maybe you can feed the dogs in a separate room, then take their food up (I'm guessing Sapphire is a dog and your profile lists another dog). That way, your sister can't get to it. If the dogs need more food than normal for some reason, then feed them several times a day like this.
Yes, I am serious. Maybe I should have posted this in the forum for vents, since that is sort of what I did in starting this thread.
As an FYI: Sapphire and our little dog Gucci are listed under Good Hope's (my mother's) name. Leo, Sapphire, and Gucci are not a problem because they are fed outside in the backyard, and we can lock that door if necessary.
This dog and his food are in the bathroom right now, and we cannot lock the doors without locking ourselves out. This would be easy if Catherine didn't know how to open doors.
I guess there are two solutions:
1) Keep Catherine out, somehow; or
2) Persuade this dog to eat better so that leaving food out all day is unnecessary.
Sofia