Boomer is the only one that is chipped, I did this after he got out of our fenced in yard and someone took off with him. Since then I had him chipped and wears and id.
As for sedating them, Boomer usually quite a wimp but did not say boo when the vet inserted the chip in him. I couldn't see having to put him under for something like that. If he was going under another procedure then getting it done at the same time would be a good idea.
I might get Kassie and Tilly done later. Boomer, due to his need to get out and roam, seem more urgent at the moment.