It's more of a precaution thing. I have a tiny boy calico that was very stressed and nippy for about 2 weeks after he arrived. I handled him during that 2 weeks to try and calm him down. He didn't eat anything (live or f/t mice or rats) until after I left him alone for a week or so. Most bps come around but its better to leave em alone for a week or until the first feed. If they feed, they are probly ok with being handled.