My rats are also from Big Cheese, and also pretty frequently bleed from the nose and mouth when thawed. However, not all of them do, and I've also had rodents from a local source do the same thing, so I wouldn't worry about it.
Your snake dinners might just require a pre-feeding facial if you think the moisture will bother your snake that much. However, they may also find the blood enticing. Haven't had this problem with rats, but there were a couple of instances when my snake did the same thing to his mice. His hide looked like he'd murdered the poor thing with an axe. I'm guessing sometimes they just get very enthusiastic about their food.
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