Rats, I just wrote a whole answer and it disappeared when I hit the wrong button. One more time ...
Is this still the foster-homes-for-turtles project? (-: Or something similar ... I think I would use the word 'turtles' (or whatever) instead of 'animals,' which tends to sound more like mammals in ordinary conversation.
I'm not sure 'stocking rate' is right. 'Rate' sounds like an ongoing or future process, not a present condition, and 'stocking' implies a comparison to fully stocked, that is, filled to capacity. The stocking rate might be, say, how fast the tank will fill up with turtles if they breed normally, or how quickly the owners plan to add turtles to the tank (2 new turtles per day?).
But it sounds to me as if what you need to know is more like population and population density: how many turtles are currently in each tank, and how many square/cubic feet per turtle (or alternatively, how many turtles per square/cubic foot)? There may be a better word for that in zoo- or aquarium-keeping; I can't think of one, but you might try an internet search with 'per (square OR cubic) foot' and see if anything turns up.
5. What kind of terrarium, tank, aquarium, or other enclosure do you plan to keep the [turtles] in? Please describe your setup below.
Technical equipment (e.g., pumps, mister/humidifier, timer):
Climate (indoor/outdoor, maximum/minimum temperatures, humidity, etc.):
Population per square foot:
Other species in same enclosure:
Additional features in enclosure (e.g., plants, rocks, caves):
Please attach/enclose recent/current photos of your turtles in their environment, or of your proposed environment for the new turtles. Thank you for understanding that this will help us be sure our turtles are going to good homes.