Ah, thanks for the heads up about the extra fat it would provide! I didn't think about that. 1/8th of a teaspoon is about 12 drops, apparently. I think I'll start with one drop, and then build it up to a maximum of 8 or 10 drops.
I'm just thinking that the diet may have gotten his vitamin levels a bit low, hence the brittle nails.
The breeder said she gives her dogs a good round of omega3 once a year, during Winter time. So I figured, why not.