Something to remember too is the age of children coming into care. In Ontario for instance most kids are 12 months when they start care so need to be developming their own walking muscles rather than being carried everywhere. That doesn't mean there aren't extra cuddles but it does mean that crawling and getting there on their own is developmentally appropriate. Not to mention some can be 30 lbs. - especially the ones that have been carried too long and need more exercise time.
HAHA, mines in the 3rd percentile for weight (hubby and myself have high metabolisms too) so i don't think I need to worry about his calorie burn!
But your right in that they do need some floor time and lots of opportunites to develop their motor skills.