Anyone had any experiences with high protien food causing nervous behaviour?

My girl is now 6 months and up until last week has always been a happy, confident little soul. She was weaned onto RC starter and when the rest of the litter went home she was changed to RC golden retiever junior. Ive had no problems with this food but since hearing lots of good reviews about F4D I signed up to the breeders scheme and as it was cheaper I thought Id try it. She was put onto fish 4 dogs puppy around 2 weeks ago.
She has always loved being shown at training and shows her socks off standing perfect wagging her tail the whole time and moves like a dream, no messing or anything. Last week she went to training and from setting off she seemed " on edge" the whole time. We pulled up and she was growling at traffic signs, we introduced her to them and she got over it. She then refused to walk in the door to training, having to be enticed. Once if there she was quite nervous of the dogs that she has met no problems before and when the judges tried to go over her she was very worried, leaning and pulling back nd would not let them go over her at all. She was fine on the move and standing as long as they didnt try to go over her. This really is not her! Nothing has happened to her at all.
We went to our first show on Saturday, again she seemed very anxious and "edgy" thats the only way I can explain it. Quite worried of the other goldens, was interested in the loud tannoy but not frightened. Then we went in the ring, she showed her socks off perfectly until the judge tried to go over her then she just freaked out. As soon as he walked away from her she was fine but if he was behind her she couldnt stop watching him and was very untrusting.

This is such a massive change of character, its quite worrying really. Could it be the high protien food?? I changed her onto a lower protien food the same day as the show but now Im worried and we have 2 more shows over the next 2 weeks. I could really do with a bit of help and advice please
TIA
Amy

Could she be coming into season?

My BT bitch has a change of moods when she is close to coming in.

Hiya, I have considered this, but very much doubt it since I know the bitches in her lines well and have never known of a season before 9 months. Although, of course there is always the exception lol. She was 6 months exactly on the day of the show so unlikely for her to come in at such a young age with her being a large breed.
However, her mother is now on day 10 of her season so could be another possibility??

Ive convinced myself its the food...Im actually hoping that it is something as easy as that and hopefully Ive caught it in time.

remember pups can go through a second fear period at around 6 months where everything that never seemed scary all of sudden seems scary.

I think, 2nd fear phase would be the most likely explanation too, it can occur from 6-14 months depending on the breed, if it is this you just need to ride it out and keep up gentle socialisation that she can cope with.

I too agree with a second fear stage, my lad who had been used to being examined by strangers from 9 weeks old suddenly didn't want to stand on the table let alone let anyone look at him he was just 7 months old, nothing untoward had happened to cause the problem.

I gave him a break from training on the table and continued with just lead walking etc and gradually reintroduced the table work after 2 weeks and when he was happy with me I asked others to get involved again, never had any more problems and at 9 months old and his first show he stood rock still on the table whilst he was examined all over, I was so proud after the hiccup we had a few weeks earlier.

Your girl will get over this given time and patience. 

Oh I really hope so...Im a nervous person in the ring anyway but I was so embarrassed when this happened at the show the other day, I couldve cried. The judge was fantastic and told us not to worry as it was her first show and it happens to the best of us. He must have liked her cos she still got 3rd place, probably on her movement.
So do you suggest I just carry on with her as normal, going to the shows and being gentle and sympathetic with her, not pushing her or shall I take a break completely? Or shall I go to training and just take a back seat and still allow people to stroke/fuss her but just not bother to stand her?
She is quite a sensitive girl so would imagine would be easily put off although she looks up to me a lot and is very in tune with me....sometimes not a good thing if Im nervous too! What I mean is, if theres something she's not sure of, if I stay calm and confident she usually trusts me 100% and gets a lot of courage if Im by her side. But this was something different, Im going to have to handle this very carefully so I dont spoil her and end her showing career before its even started!

Any ideas are welcome please, thanks

My girl came in season at 6 months and 2 days. She did very similar to your pup, so I definitely wouldn't rule out the season.

If it were me I would give her a short break and work on what she is happy with. Either way I don't think a break will do any harm, but it will avoid her learning an inappropriate behaviour. If it is a fear period, the last thing you want to do is keep putting her in scary situations that she can't cope with.

Thanks all, if nothing else I feel a little reassured that this is hopefully just a stage she is going through.
I will keep you all updated on how she goes
Thanks again

> Im a nervous person in the ring

Have you considered using rescue remedy ? i swear by it.