ive recently been trying to get a lucky egg in my gen4 games as in: diamond pearl platinum heartgold soulsilver
but mostly soulsilver and platinum in platinum I can never get mr backlot to say that there are chanseys and I can never get a swarm of chansey or in a route where they are in soulsilver any suggestions?
All I can say is to continue your search and eventually one will show up. Although if you ever plan on getting either Pokemon Black or Pokemon White, I'd wait until then considering you wont be able to trade it over. Also, you get one for free!
Best of luck on your search!
Dex Master