Hey again, sorry for the delayed response.
For future reference and for my ease of writing, older dog's name is Sascha,
and younger's dog name is Sergei (and no, i'm not Russian).
I really don't know if Sergei considers me as part of the pack, and if he does, I'm definitely the alpha.
Sascha is really really old so I have the vet coming over at least once a week, so there's no infection (or none that the vet could find). She's as well as she can be, considering. In the time that has passed since my first post, Sascha has completely lost her sight, hearing and most of her smelling senses. She has lost control her back legs, her bladder, and her weight has really dropped. I can actually see the bones through her skin, although she used to be quite fat (and no, she has no parasites).
Back to the subject, I wasn't in the room when the chewing/eating happened but I'm sure there wasn't any fight because there wasn't any barking or growling. Granted that Sascha hasn't barked in over a year but Sergei is really not the quiet type, quite the opposite, he's always voicing his feelings. After that incident we've kept them separated most of the time and they've only been together under close supervision. And when they're together, he ignores her. I've had more than one dog for most of my life and this really is the first time I've seen this behavior. But then again, I've never seen a dog's state degrading as fast as Sascha's, I'm open to any conclusion.
We also have one cat that we literally saved from a certain death, by the time Sergei was a puppy, and the cat has a somewhat aberrant behavior (but this is another story). Maybe Sergei is considering the cat as one of the pack, and thus the three dogs theory.
I know it sounds terrible. I wish thing would be different. You have to understand that she has been my dog for almost 19 years and I love her more than anything. But unfortunately a dog's life is shorter and we have to cope with this.
Other than this, I really don't know what other info to give you. This is a first for me too. Just add this to the list of possible abnormal behaviors.
Thank you !
Ever since I found this forum I read every post on every thread and I'd like to say thank you for being here