Dog becoming snappy on walks

[aprilshowers2015]

Wondering if anyone can help with tips/advice please.
DDog is 4 years old, she is a mongrel with bits of spaniel and shitzu, 12kg so medium sized. She was from a rescue litter but was born in foster care and has been with us since 9/10 weeks so no previous problems.

She's starting to become snappy towards other dogs if she is approached, particularly bigger or bouncier dogs. As soon as they touch noses she snaps them away. She's ok if she approaches them first but I've noticed she's stopped doing that.

My mum kindly walks her some days which is a great help as my husband is away most of the week, I have a toddler, work full time and 8m pregnant. My mum is a more nervous walker, I've only noticed this recently but it coincides with the change in the dog's temperament. Mum seems to think every dog is going to attack (daily Mail reader) and gets a bit panicked and calls her away. I can't help but think this has led to the dog becoming more anxious? DDog was fine with my husband but now doing it on their walks too.

She's very well trained, excellent recall and commands etc and I do admit I call her closer when I see a dog bounding over as I know it's going to end in a snap. I would put her on the lead but then wonder if she will be more anxious (no one seems to understand the "don't let your dog bound up to a dog on lead" rule around here). She's good friends with a GSD and a boxer but she's known them her whole life. She plays so nicely with dogs that she knows and I try and tell her to play when we're out but she's just too anxious.

I'm considering the following:
-firmer "no" when she snaps
-trying to find a "pack" to walk with
-dog behaviourist (and bring mum along to the training)
-use a dog walker a couple of times a week

Any other suggestions please? Thanks for reading.

She sounds like for some reason she has become anxious when a dog approaches, for now I would avoid dogs she doesn't know. The more she snaps the more it becomes a habit I think. Obviously you can't avoid all dogs, and I agree about people letting their dogs run over is not on and very annoying.

I definitely would not say 'No' or be negative in any way when she snaps, this will make her more anxious as she needs to know that being close to you is safe and you will step in for her.

Can you get her attention as soon as a dog approaches and start walking briskly away. I would calmly block any dog by standing in front of yours.

There may well be all sorts of other signals she's giving to the dogs before snapping, telling them to give her space. It could be just that as she gets older, she's not that keen on interacting with strange dogs.
Snapping is her language, please don't tell her off for it.
I'd focus on minimising interaction with strange dogs and help your mum and DH to do the same.
I'd think if she's not keen on other dogs - and there's no reason she has to be! - then a packwalk might just be super stressful.
It's probably more your mum's & your DH's behaviour you need to change, than your dog's.