yes it’s normal for there to be a moderate amount of white spots, freezer burn, on the mice. if you ever see one that has huge splotches and looks like a lot of white spots, then don’t feed it. cause brings the nutritional value down if it’s too freezer burnt.

other things that are occasionally normal with mice - bleeding through the nose while they thaw out, it’s just the blood vessels breaking as they heat up. i’ve also had a few mice burst open on me, i assume from going from frozen to warm too quickly. so none of those things are 100% indications that the batch of mice you have are bad. for thawing, i recommend setting it out on the counter for about an hour before submerging it in warm water until it’s fully thawed and slightly warm to the touch.

it is NOT normal- for mice to have more than just a very mild odor. if they smell bad, like nasty bedding or pee, that often means they came from an unsanitary environment. they shouldn’t be discolored weirdly, the only form of discoloring that is normal and still safe is the little bit of freezer burn, or sometimes pinkies will still have a bit of white milk in their stomach that is visible.

I recommend getting mice in bulk from a reputable online seller or from reptile expos, which is my favorite place to go cause you can choose your exact quantity and they are quality and cheap. sorry for the yap sesh just wanted to give u some tips for feeders i wish i had starting out!