snails - DOA?

Hi! I'm a newbie so forgive the ignorant questions! I just introduced my first group of fish and critters (from LiveAquaria) to my reeef tank yesterday. They joined 9 hermit crabs that I caught locally on Sunday. I drip-acclimated everything and the water parameters are perfect. 3 snails have not moved since I placed them in the tank. Should I take them out and look for signs of life? Which would be - ??
Also have a feather duster that appeared DOA but is in the tank. (another thread)

Thanks for any advice!