[Hall of Famer]

Thanks for the comments everyone, I really appreciate all these. I am not sure if a battle system will be available anytime soon, it may not be possible even during next summer seeing how many pre-requisites we will need for a battle system to function well. Not only the HP of a pet can be integrated to a future battle system, but also other stats such as attack, defense, speed and so on.

@ gigi:
IV = Individual value, which is a random number between 0 to 31. A pokemon with higher individual value is usually stronger than others of the same species.
EV = Effort Value, which is a number that increases through battling. Seems that the effort value of your pokemon is largely dependent on the enemy pokemon you defeat, which is too complicated to be implemented into this HP system(so of course, I neglect this effect for pokemon's HP determination at this point, at least until a battle system is added).

Also note that in reality, a pokemon can have up to 6 different Individual and Effort values for each of its stats. For instance, your pokemon may have rather high HP if its individual value for HP is 31, but in the meantime its individual value for Speed may be low so you always get hit by your opponent first. The same applies for Effort values, which becomes a problem if you try to add all these columns to your owned_adoptables table(lemme see, 20 new columns at least). This is why I am considering whether to create a new table that stores data for each pokemon's stats with references passed by adoptable ID numbers.