Yes, but there's only one evolution track per pokemon (except Eevee which has 3 in gen 1). The optimal strategy for grinding experience is to catch a million pidgeys and evolve them all into Pidgeottos for the experience and then transfer them because Pidgeot isn't that powerful of a pokemon. The optimal strategy for building the pokedex is to catch enough pidgeys to get a Pidgeot and then you don't need to catch any more pidgeys.