Defensive Rescue Dog

Question
Hi Nancy,
I'm hoping you can give us some advice on how to deal with our little rescue dog Mia.
We have a 3 year old Beagle neutered male called Mr Budley who is very placid and super friendly with other dogs.
We have recently rescued an 8 month old cross breed neutered female (Mia) and she is doing very well with us but keeps snapping at Mr Budley and we aren't sure how to stop her from doing it.
Mia comes from a very bad background, she was found at approx 3 months of age wandering the streets in Romania, she has been in a shelter there since then but the shelters are pretty horrific and the dogs need to fight for food and constantly defend themselves.
Mia is painfully thin so we are currently trying to put some weight on her, she is also covered in scars from being attacked by other dogs in the past.
Mia interacts quite well with Mr Budley most of the time and she is happy to sleep right next to him and even kisses his face when she gets a chance, however as soon as potential food becomes involved she is vile towards him.
We completely separate them to eat there meals but if any situation occurs that Mia thinks could possibly involve food for instance if I am eating my meal and Mr Budley tries to come in the room, Mia will snap at him, the same happens if I am preparing food in the kitchen and Mr Budley tries to come into the room she will snap at him.
Mia allows us to take things away from her and she shows no signs of jealousy when we give Mr Budley attention etc. We think she is just used to having to defend her food aggressively and maybe also a bit frightened. She has occasionally snapped at him for no reason but 99% of the time there is some sort of food link.
Poor Mr Budley just runs away from her when she snaps but he is looking pretty fed up with it. He doesn't trust her at all and you can see he is nervous when he is trying to come in a room and she is already there.
I think they could potentially have a great relationship as they forgot themselves earlier today and started playing together, also when the are out in the local park they walk along really happily together and Mia constantly pokes him affectionally with her nose. They also sleep together fine and she follows him around for ages in the garden sniffing and checking things out.
We are currently just saying "No Mia" in a loud firm voice when she starts snapping but im not sure its working. We aren't sure if thats the right thing to do and we don't want to make things worse for either of them. We have also been trying to give Mr Budley the top dog perks such as feeding him before her and giving him his treat first etc. Mia was terrified when she first came to live with us and although she is starting to trust us and is much more comfortable now she is still nervous and we don't want to upset her.
Mia struggles at the moment meeting new dogs and initially raises her hackles and snaps and growls while at the same time cowering behind my legs. We are trying to socialize her gradually so hopefully she will soon start to realise that she wont be attacked and that she can relax and play with doggie friends.
Mia is a lovely, sweet, funny little girl and I think her general nature is to be friendly but unfortunately her circumstances have left her a bit frightened and feeling like she has to defend herself and any food she can get from other dogs.
Apologies for this question being word heavy, if there is any advice you can give us we would be very grateful.
Many thanks
Sarah

Answer
Sarah,
When a dog is starved and has to fight for food, it is very hard to change things around.  Hopefully, due to her age, you can turn this around.  Keep a leash on her so you have some control.  You are going to have to set this up, but even before you do, there are some preliminary things you must do.  She will feel a whole lot better if you stop babying her and feeling sorry for her, if you are doing that.   You must become the "Pack Leader" of your little group, this way she will learn that she doesn't have to fight for her food, you will provide for her.

You start this by being a drill sergeant.  She must learn that you eat first, and she is not allowed to walk out a door without you telling her to do so.  This goes for your beagle too.  You must show yourself as a leader to both of them.  Don't be mean, just consistent in a calm, assertive way.  Teach her to sit, down, stay.  If she becomes agitated, wait her out until she gets calmer, it is then that you pay attention to her.  After she knows these commands and she knows you are the one to make the commands, start with the food aggression.  Have both bowls ready,  tell them both to down, stay.  when they each do this give them their food.  

If she starts growling or snapping, you snap the leash and put her back in a down, stay.  Make sure you are right there at all times and giving off a feeling of "NO NONSENSE, YOU TWO".  This would be what a pack leader would do.  Keep putting them back into a down, stay.  Which ever one is the calmest gets their food first.  If you could order Cesar Milan's Pack Leader DVD you would be able to see first hand how he does it.  He uses his body language and his emotional calmness to bring calmness to the nervous dog he is working with.  I do the same thing, even before I knew of him, but I don't have a DVD out there. lol.   

If you have more questions, please let me know.  I think if you follow the above attitudes, you will be projecting to her your calmness and she will calm down and be less afraid.  Remember she has been alone all this time, no one to help her.  Now, you are going to take her worries away and be strong so she can relax.  See how her mind works??  She will be able to relax if you take over her problems and give her smaller ones like sitting, down, stay, eating calmly.  These problems are much less stressful than, if I don't attack, I will starve to death.  See?

Nancy