Use Theif On A Wild Chansey
Shroomish is not available to be caught in the wild in Pokemon FireRed, it must be traded from Ruby or Sapphire.
Wild Chansey
Actually, I think that is a Johto region pokemon, and seeing as Firered is a 1st gen remake, which is set in Kanto, you can't find it in the wild. You might be able to trade for it.
I do not know what Pokemon you like, so try going to www.serebii.net and find the Pokemon you like, then look where they appear on FireRed.
Wild Chansey can sometimes hold that item to find Chansey go to the safari zone.
Wild Chansey are found in the Safari Zone. It's a rare encounter and is difficult to catch, along with the fact that it can flee at any time during the encounter.
you can't unless you trade it from another game.
In the wild.
Use Theif On A Wild Chansey
Shroomish is not available to be caught in the wild in Pokemon FireRed, it must be traded from Ruby or Sapphire.
You cannot find Piloswine in the wild on Pokemon FireRed. You can find it's pre-evolved form Swinub in Icefall Cave on Floe Island in the Sevii Islands of Pokemon FireRed.
You can get them from Chansey. Capture a wild chansey and they always carry one with them. I just checked 3 chanseys that i have and they're all holding one.
You can't. You have to find and catch a wild doduo in the safari zone and evolve it.
Wild Chansey
Actually, I think that is a Johto region pokemon, and seeing as Firered is a 1st gen remake, which is set in Kanto, you can't find it in the wild. You might be able to trade for it.
On route 222 you can find Electabuzz.Those Pokemon hold them in the wild sometimes when you catch them