My royal is a little over 1 year old and weighs 603 grams, the pet shop I bought her from was feeding her an xl mouse (35 grams) every 7 days, upon research I thought this to be too little too often for her age and weight so I upped her to jumbo mice (the frozen one I’ve just weighed was 43 grams), so that would be 7 ish percent of her body weight and I’ve been feeding her every 10 to 14 days which is apparently fine according to some reddit threads, but im also reading in other places that she should be eating 10 to 15 percent of her body weight not 7!! Should I up her to rats and contue to feed every 10 to 14 days? I think my pet shop does a 60-65 weiner rat if I’m not mistaken which would make it roughly 10 percent. Also I’m conflicted on weather 603 grams is a good weight for her age, sorry I’m New to this and the variation of information on the Internet can be so confusing
I feed my balls every 7 to maybe 10 days. As far as size, I try to feed a prey that is about the same size around as the snake if not a little smaller. That makes it so the snake has a slight lump in him/her. The lump shouldn’t be too big, just big enough that you can kinda see where in the snake the rodent is.
I do once a week until they’re one, then every two weeks until they’re two, every three until three, and then once a month when they’ve turned three. So about every 14 days sounds fine at just over a year. I use the 10 percent rule for larger prey items (rats typically), but i also feed chicks which are smaller. If the last meal was a chick i might feed a week early, if it was a rat, i might wait an extra week 
The 10% or slightly bigger than the widest part of the snake rules are really just guidelines. They’re easy to remember and make sure that you are feeding a generally appropriate sized meal.
I feed my hatchlings every 5-7 days. From there they go to 7-10. And my older snakes are a bit of a mix depending on things like breeding status or weight. Anywhere between 14 and 21 days generally. If they look like they’re getting a little too hefty I cut back how often I feed. If it’s coming up on breeding season I may offer my females a snack in between meals.
As far as the appropriate sizes…it really is a matter of individuality. For example, I have a healthy weight male at 2000+g. I also have a 4 year old female at 1050g.
Just like people they can grow at different rates and sizes. As late ng as your snake’s body condition looks good, I wouldn’t worry
I feed my BPs rats that are 10% of their body weight once a week, 15% body weight every 2 weeks and they maintain a healthy weight with this routine.
I’d reccomend switching her from mice to rats as soon as you can, they don’t have the nutrients rats do that BP’s need as they are much closer to a BP’s natural diet and as she grows larger she’ll need larger prey. And as @autumngeckos mentioned you can feed them chicks sometimes but just be sure to feed sooner after the chick meal, if you have a BP that is picky I’d be careful feeding chicks as BP’s can switch pretty fast on you and refuse to eat anything else.
I agree with above comments, it seems like what you’re feeding now should work well. I do hatchlings every 7 days, juveniles every 8-9 days, subadults every 10-12 days and adults every 14-16 days (and I breed, so my girls need a little extra to make sure they can support egg laying). Mice will be fine for a while, but I second getting your snake on rats - not necessarily for nutrients (as far as I’m aware mice are plenty nutritious) it’s just that mice only get so big and your snake will need bigger meals eventually.
Thanks for the reply guys, I’m swapping her to rats tommorow, I think my pet shop does a 60 gram weiner so that also works with the 10 percent rule for a while, and ime going to feed her every 7 to 10 days.
I’ve also been told 603 is under weight for her age what do you guys think
For a year old, 603 is completely healthy honestly. You’ll hear people saying they’re small because so many breeders feed so much more than is necessary to get animals to breeding size sooner. On my feeding schedule, I generally expect my animals to be between 400-600g at 1yr, 800-1200 at 2yrs and 1600+ at 3yrs. Honestly, her body condition looks a little on the chunky side, so spacing feedings out is probably a good idea.
Yup, big agree with @inspirationexotics
She looks great. Beautiful girl.
I’ve raised most all of my collection from hatchlings over the last 3+ years. My females weights are all over the place. Some are 1200, 1300, 1400, 1600, 2000 and a couple are still under 1000 grams. They all have their own personalities or you could say habits.
I have my entire collection on a 14 day feeding schedule. Some won’t pass a meal up while others for one reason or another just refuse food at times. We can give them everything they need to thrive but can not make them eat when they don’t want to. The ones under 1000 were stuck on mice and were more difficult to switch to F/T rats.
Those I would refer to as my problem children.
I agree with @inspirationexotics and @armiyana, your girl at 603 grams looks to be in great condition and is gorgeous.
I wish you all the best.
Thankyou guys, as a new owner its reassuring and I really appreciate the help