Ive had 2 rats put to sleep and theyve both been done by different vets and different methods
1. Fudge was anaesthetised then injected with bright blue stuff into his abdomen i think (possibly his leg i cant quite remember) and it took a good few minutes for him to pass
2. Today Peanut-Butter was anaesthetised but injected with yellow stuff directly into his heart and passed very quickly
I did ask the vet why it was different and she said it varies depending on what method each vet prefers.
I know the heart one can hurt if they arent anaesthetised but she assured me he wouldnt feel anything.
Personally I preferred the first method, it just seemed a little bit nicer and i think next time i will ask to only see a vet who does it this way, injecting into his heart just doesnt feel like a nice way to go even if he was blissfully unaware

Amy