Gapeworm treatment and how soon can you eat the eggs

Hello!  Thanks to all you posters out there that helped me diagnose my chicken with gapeworm.  She's been hiccuping and wheezing for about two weeks now but other than that she's been fine.  I have been doing a lot of reading up on treating gapeworm and found that fenbendazole is the only really good treatment out there.  But I'm concerned because they say you shouldn't use this for any birds producing eggs or meat destined for human consumption.  I'm assuming that it will eventually go out of the bird's system so how long before I could start eating her eggs again after treatment?  No guesses please!!

Also, how the heck do you look down a chicken's throat to see if they have red worms in there?? 

Thanks for your help.  I decided to try and treat Buttercup with Piperazine first.  A couple of people have said that worked for them.  I will also try to look down her throat today and see what I can find.  I know I let my chickens out about once per week to scratch for bugs and worms in my backyard here in the San Diego area, so that's why I thought it could realistically be gapeworm.  Everything checks out for that other than looking down her throat.  I'll keep you posted.  :|

Thanks, this was several years ago and yes, it turned out just fine.  Buttercup is still with me and healthy as ever.  Unfortunately, I had another chicken contract something that looked like gapeworm in April and after several treatments, didn't get any better.  I couldn't stand to see her suffer with her breathing anymore so I had her put down by a local vet.  As they say, you win some and you lose some.  I just hate the losing.