rottweiler snapped at friend
My male rottie 2 years old was microchipped and had his booster on 19th april. He wasn't as active as normal before this and when he came home was sick twice. Next day he was vomiting blood so took him to vet.
She injected him twice and gave us antibiotics for him. He went a short walk where we met a man who chatted but when he went to pet him he gave a growl. He has always been so friendly up to this point. Is it because he was feeling ill.
Personally I would bet that this behavior was triggered by the fact that your dog wasn't feeling well, and may be in pain or discomfort.
It sounds as though he had an adverse reaction to either his shots, or the implantation of the micro-chip, and hopefully this will be short-lived. If the site of the micro-chip or the vaccinations was tender, he would not want someone touching him - especially someone he didn't know.
I wouldn't worry too much about this isolated incident as he's never acted this way before. Chances are excellent that as soon as he's feeling better, his good nature will return.
I hope that he gets over whatever it is that's causing his discomfort very soon. Best of luck with him.