Hidden Power doesn't work like that.
Hidden Power is a move that is based on your IVs, or Individual Values. These values range between 0 and 31 and the higher they are, the more they increase the stat they are in. (There are 6 IVs for each stat.)
The IVs are then plugged into a formula that generates the base power and type of Hidden Power. This or your IVs cannot be changed.
So if you face Taillow or Swellow, your Hidden Power would still be what it was before.