Are you feeding every 5 days religiously? Do you just feed their width or a % of body weight? I mean I'm sure you're not weighing out each rat but I'm sure you ballpark somehow. It's crazy to me how I've even seen some variance in my small collection with my bigger snakes growing like weeds but the smaller ones seem like it takes them a while. But I'm sure I just look at hatchlings like they should be putting on the same weight gram for gram that my bigger snakes are doing. I have two girls that I got on the same day and they've both eaten well (biggest has skipped a couple meals due to not swallowing or turning down in shed, maybe 4 times total), the smallest one went from 103g on Nov 7 to 281g today while the bigger girl went from 454g to 792g. The bigger girl seems like she's gaining so much more but she's only almost doubled while the other girl almost tripled.