Adopted stray Hungry all the time

Question
3-11-08 - -i adopted Virginia a Stray Coonhound Mix, she is guesstimated to be about a year old, she was spayed March 2008, at her first vet appt. she weighed 33#.  Since that time I believe she has put on a few more pounds (she was thin-ish)
She eats Nutro Natural Choice Lamb/Rice, at least 5 cups a day (split 2 1/2 morning & evening) the amount has increased since march (when we noticed she seemed to be starving!) She will also if given the chance eat her own stool (however having a toddler using the same backyard the stool is removed almost immediately so she can't eat it and the toddler can't fall in it, even without the toddler who wants a stool-eater!)  She also resides with a senior mix breed (13+) who eats Nutro natural choice Senior chicken, i think!  i recently switched from Iams Adult. They also get treats, biscuits and some 'people food' thanks to the toddler.
I would rate Virginia's activity as HIGH.  She walks at least twice a day full speed for about 10 minutes each walk.  And plays in the fenced yard. . .she likes to race and is very fast!!
because she is spayed I fear alot of weight gain if I increase the food even more, but my gut tells me the poor thing is still hungry.
Any advise is greatly appreciated.  I'm not a Breeder. . .I work at a Non-profit Animal Shelter.
Thank you Caroline

Answer
Perhaps you see so many underfed dogs at the shelter that you don't understand that is normal for many dogs to always be hungry.  The Labs that I know well, are some of the worst.  I am not sure where Coonhounds fit in.  The trick is to feed them what they need, and if they are still hungry, it is normal.  Feeding some dogs enough to satisfy them would lead to over weight, all sorts of health problems, and an early death.  

Your dog definitely should be narrower at the waist than the hips and chest. You should be able to easily feel the ribs, but not see them. Each dog is different. Standard recommendations are a good place to start, but each dog must have its food and exercise adjusted to its individual needs. Here is a link to a good illustrated guide, http://www.longliveyourdog.com/twoplus/RateYourDog.aspx

Quickly cleaning up after her may be your best strategy especially with the toddler.  You could try adding canned pumpkin or grapefruit juice to her food,