We have a 5.5 month old Jack Russell pup and for the last week her behaviour has become really erratic and strange at times. Examples include suddenly pacing the floor whining and barking, excessive barking and licking herself, she's just in general very unsettled and becoming more mouthy than she is normally. We've noticed on walks she is pulling quite aggressively to get near other dogs and if we move her away she cries. She's also started to wee in strange places (middle of the pavement for example) where she normally has set places on our walks that she would go.
She's generally extremely well behaved, has a good routine (that she established herself) and is usually very chilled and easy going (for a terrier anyway). She is well socialised and exercised and has lots of enrichment play so I'm certain it's not boredom causing this.
Could she be entering her first season? Google has been conflicting in terms of guidance so hopefully someone here will be able to help! We will be getting her spayed however our vet recommended allowing her to have one season before doing so which is why she hasn't been yet.