Nobody has ever mentioned this, but most people handle the prey item with their hands hence "scenting" the prey item with human scent - the animals (especially rosy boas) seem to key in on this.
You can hook a rosy out & be handling it, & it will just kinda turn its head & start chewing.
For whatever reason, triv trivs don't seem to exhibit this behavior, especially when compared with a coastal or desert.
Rosies can make great pets - most people who are breeders don't take the time to treat them as pets - just open the cage & feed them - thus creating the feeding response.
Good luck & enjoy your new rosy.
Cheers,
Max
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"I may be crazy, but ya know... I can rationalize just about anything."