Hi hope! All but the very smallest neonate boas can handle rat pinks or pups as opposed to mice. A rat pinkie or pup with a body circumference equal to your boa's widest body girth is the proper size to feed. If calcium is a concern, ( why some folks will recommend mice rather than rat pinkies ), you can take your thawed rat pink or pup, defrost in warm tap water, pat it dry with a paper towel, and roll it in some Rep-Cal Phosphorus-Free Calcium with Vit. D3 Ultrafine Powder. A rat pup of a few days old will have more sufficient bone growth, hence the addition of supplemental calcium is unnecessary. I have Colubrids that I used to feed mice, due to the recommendations of many with respect to the Calcium issue-( i.e.-feeding a rat pinkie versus a more developed mouse with more advanced bone growth ). However, I quickly learned that even the smallest of rat pinks or fuzzies are much more nutritionally proficient than any mouse. Mice are virtually "garbage in; garbage out", whereas a well nursed and fed rat pink is a much preferred choice for my crew!
Not certain how small your new RTB neo or juvie is with respect to girth, but if he/she is getting 3 mice fuzzies or pinkies, I'm sure you would be much better off IMHO to feed a rat pink or pup of the above described equal body circumference as your little RTB's widest girth! If he/she is 18" in length, it's likely ready for a pup of least 3-4 days of age or thereabout. HTH! Post some pics if you can!
