5 grams is on the smaller side, but perfectly capable of eating a day old pink (a red) if it _wants_ to.
To prepare boiled pinks, which I REALLY like, now, for baby's first meal, you boil water, place the desired amount of pinks in a small container, pour boiling water on them, serve immediately.
In the past, before I got good at feeding tricks, I thought "boiled" was the same as "really hot." It is not. I used to heat pinks, mice, everything, in tap water as hot as it would go, which at my house is 120F or so- hot enough to heat to mouse body temp but not enough to flash cook. I _never_ had any luck feeding "boiled" pinks to a non-feeder.
Then I tried actually boiled cooked pinks and my stubborn feeders gobbled them down like they were the best thing ever. Another plus is they keep a lot better than uncooked pinks- you can leave one overnight and it doesn't rot.
Another good lesson I learned that season was that all dish soaps are not created equal, and that Ivory original liquid is the most-preferred brand (by discriminating hatchlings) but blue Dawn was also well-received, and yellow Joy might also work. If a snake doesn't like Ivory, that doesn't mean it won't like Dawn. You have to try at least the top three.
If you look at the link that DollysMom posted, it goes to a HUGE list of feeding tricks/advice.
Another thing you should perfect before you need it, if you have a bitey hatchling, is tease feeding/slap feeding. This is another thing I was doing COMPLETELY wrong. Everyone calls it "the pinky dance," and that is complete BS for getting a non-feeding baby to feed. What you actually want to do is jab the pink into the hatchling's neck, and it will almost always reflexively bite, at which point you freeze and pray for swallowing. There's a video, for sure in Susan's personal forum, but if you can't find it, hit me up and I'll find it for you. You do not need to use live pinks.
Thirdly, it's been pretty well-documented that some non-feeding hatchlings just aren't big enough, developed enough, something, to have the urge to feed, and if you offer one or two feeding tricks each meal, and the hatchling refuses, so you assist feed it- it will grow and gain weight and eventually go on to feed itself at some point when it matures enough. I've been feeding a hatchling who I took over when it weighed 3.8 grams or so. Just a few weeks ago she started willingly reaching out and biting a pink (with me holding her, and the pink). I'm hoping she's within a few weeks of making the connection to sit in a deli and pick the pink up herself. But it's been about 10 or 11 months of me assist feeding her, taking her on every vacation, just not giving up. If you wait too long to begin assist feeding (I only give them about 3 opportunities to refuse, 3-5 days apart, and I also don't even attempt to feed until a week after the first shed, and some people wait two weeks, to make sure the yolk is completely absorbed and the baby is REALLY hungry) the baby loses too much condition and is impossible to save once you do give in and start assist feeding.
But back to the original baby in this post- I would bet it hasn't been offered any meals at the breeder's, so can stand to have two or three tries with different "tricks" before the owner needs to think about assist feeding it.
To clarify: For the first meal, I offer boiled, in a deli, covered, don't peek for an hour. If the baby doesn't eat, I reheat, and leave it overnight. If the baby doesn't eat, I wait 3-5 days, and then try boiled again, possibly scented with Ivory. If the baby doesn't eat, I try slap feeding to see if I can get it to bite. If it bites, it eats. If it doesn't bite, I might try a different soap, or chicken juice, or something, and leave overnight. Same thing 3-5 days later. If it still hasn't eaten, on the 4th attempt, I'll assist feed. Once I start assist feeding, I still offer different tricks first. I don't feed when the baby is blue. Often, after the shed, it will have gone long enough without feeding and is hungry enough that that is your best shot at it actually beginning to feed. But- just keep at it, don't give up, they virtually all eat eventually, usually in just a few weeks.
Iwill update once she feeds