Becoming Aggressive

[Dee_Marie]

My 9 year old soon to be 10 year old Border Collie/LabX Missy is becoming aggressive. A little background Missy is Dog reactive and snaps at kids who are being loud, roudy or running. Tonight she attacked my cat Sophie who has been around for around 7, 8 years because her and Bone's our 7 month old kitten was bugging her which was causing her to be tense and hissing. Sophie is a mostly outdoor cat who can come in whenever she wants. Bone's is strictly indoors. She has pounced Sophie before for darting onto the porch.
Recently I have found her not allowing Bones to move from where he is. It's at the point that he doesn't feel he can walk into the hallway which leads to rooms without being pounced and growled at by Missy. While Bone's is on my bed she will sharply bark and run toward him if he moves.
She also guards my bird Toby when he is on the ground(can't fly) she does not allow other animals near him.
Missy is also wanting to eat my new bird have had him for a month, she spends a good part of her day staring at him, but is becoming less obsessed with him lately(I have been working on this and am making progress.
Last but not least she is also being mean toward PIper my 2 year old Bully breed(American Bulldog, Staffy, APBT??) They were always best friends playing together and Missy was very tolerant of Piper when she was a puppy. Piper will no longer sleep in my room because Missy growls and snarls at he when she comes in. I will have to put Missy in a sit so Piper can get on my bed.

Any suggestions, training tips are highly appreciated. All this is pretty recent as in months maybe 2 or three.

[Erica]

My first suggestion would be a thorough check from a vet...nine years old is getting into "senior" years for large dogs, and if Missy isn't feeling well it may be manifesting as less tolerance for things that annoy her. If it is medical, training won't really address the root of the issue so good to get an all-clear from the vet before trying a training plan!

[JudyN]

I agree with the vet check. And in the meantime, assume that either she isn't feeling great, or she's becoming naturally cantankerous in her old age, just as some people do, and manage her environment to remove the 'irritations' as much as possible. Make sure she has a safe place to go to (e.g. a crate, if she's used to one) where she won't be bothered.