Hi
I'm glad that you appreciate they shouldn't breed, being brother and sister. I have both male and female Jack Russells and they are both neutered, so it is my advice to get yours both neutered. It is a simpler operation for the male(assuming his anatomy is all normal and there's no undescended testicles) I am a firm believer in neutering dogs that you dont want to breed from and in this case there's no question that you shouldn't allow that to happen. Modern pain relief makes the neutering procedure relatively untraumatic in young fit dogs so I dont think you need to feel bad for either dog.
Cathy Wickenden BVet Med MRCVS
Barton Lodge Veterinary Centre
1 Midland Road, Hemel Hempstead, Hertfordshire, HP2 5BH
Tel: 01442 216048 24 hours
[
www.bartonlodgevets.co.uk]