6 year old Westie suddenly becoming aggressive with other dogs when we have food??

[SagaNorensLeatherTrousers]

Hi,

A quick initial google tells me we should probably consult a professional trainer but I would like some quick advice/insight to what we might be dealing with here?

Normally our dog is a friendly girl who used to be walked by a dog walker every week and was visited by my MIL's friend with her dog once a week as well...never used to show any aggression towards either dog. Never had issues around them when food was out. MIL's friend used to keep treats in her pocket and would give them out to both dogs equally.

About a month ago we bought some fish and chips and took them over the field where lots of people walk their dogs. I noticed that she seemed to circle around us a lot and wouldn't relax. If a dog came a little bit near she'd run after them and in hindsight I remember thinking she seemed...not aggressive as such but not relaxed or playful either, like she was on edge. I just thought I was reading her behaviour wrongly and no dog got near enough for her to show she didn't like it or whatever so I didn't clock it as an issue iyswim.

Well, today...my DH and I decided to take her and our 15 month old DD to the dog-friendly beach with a PICNIC. The beach was really crowded with a lot of dogs running around. She seemed fine at first, would go up and sniff and run happily away and stuff, all normal behaviour.

Until we busted out the picnic. All of a sudden it was the same circling behaviour, on edge, acting alert, etc. We were about 15 feet from another family with a few small dogs. We had two incidences where one of the little dogs came running over to sniff at our Westie and she went berserk, basically snapped at them and seemed to want to really attack them! Again, the 1st time wasn't that bad and we thought she was just annoyed that the dog got right in her space...The 2nd time it was much more aggressive...our Westie seemed like she really wanted to and would hurt the pug. There was no mistaking the aggression.

The owner quite rightly got cross and shouted that we need to put our dog on the lead and kept going on about the fact she did it twice. I think we were such in shock about her behaviour, I explained she wasn't usually like it, we're sorry, etc., put the dog on the lead and left. We were embarrassed, and upset and shocked by it all.

So what could this be? She's normally healthy, happy, completely tolerant of my kids tripping over her and tugging at her ears, etc. I'm starting to worry about whether she'll turn on them, though!?

She's fed every day at same time and never shows signs of hunger. She is due a vet check-up so of course that is first port of call, but I was wondering if anyone possibly had any ideas as to why she's changed?

I feel like if we take her out near other dogs we'll need to muzzle her or something! When have you ever seen a Westie that was muzzled?

[SagaNorensLeatherTrousers]

Should also add: My Dh or I take her for a walk off-lead every day at the same field where we had fish and chips and she's absolutely fine. The aggression seems to come out when we have food.

I don't feel it's enough of a solution to say we just won't bring food out with us.