Mice are a relatively small meal for a subadult ball (I'm guessing by sub adult your talking somewhere around 600 grams) - I have a girl 900 grams that will eat 4-6 mice every week like they are popcorn - if she would eat rats it would only be one medium one - but alas she is stuck on mice. I also have a 300 gram male that takes two mice per week no more no less. Generally feeding once ever 7-10 days is recommended but that depends on the snake, the size of the food item and how well they digest. I've got one girl that will only eat once a month - it doesn't matter if I give her a huge rat or a small one - she only eats once every 28 days.
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Tosha 
"Stupid is forever, ignorance can be fixed." Don Wood
"Of course, that's only my opinion...and I believe I am God." =) Chris Bianco
7.33.0 Ball Python (Harry and Fluffy and gang)
1.0.0 Angolan Python (Skywalker)
0.0.1 Green Tree Python
0.2.0 Feline (Pippen and Pandora)
0.0.1 Dessert Tortoise (Pope John Paul)
2.2.1 Fish (1,2,3,4)
0.0.0 Pool skimmer rescues for this season