Let's take a look at the stats shall we
Pidgeot
HP-83
Attack-80
Defense-75
Sp.Atk-70
Sp.Def-70
Speed-91
Fearow
HP-65
Attack-90
Defense-95
Sp.Atk-61
Sp.Def-61
Speed-100
As you can see, Pidgeot's stats are more evenly spread.
Fearow was meant to be a sweeper, just look at that low HP, Sp.Atk and Sp.Def. It's got high attack, defense and speed. Pidgeot can take a few hits and can give out a few too but I would go with Fearow since he has a higher Attack, Defense and Speed.
Let's take a look at the movepool.
They both have ludicrously small movepools.
Movepools almost equal.
Now I like Pidgeot but Fearow is better for sweeping compared to Pidgeot.
Moveset for Fearow
-Fly
-Steel wing
-Tri attack
-Drill peck/toxic
Moveset for pidgeot
-Fly
-feather dance/toxic
-steel wing
-aerial ace
As I said, in gen 3, Fearow is better.
So go with fearow.
Hope I helped!