Deworming urban chickens

I have a bit of a funny story - Our chickens lay pretty steadily but two of them have been kind of slow in that department since the summer. About a month ago, I found a round worm in the yard and figured that it probably wouldn't hurt to de-worm the ladies, in case that is their problem with laying.
My first (hasty) thought was to call the vets' office to get de-worming meds. Did I ever get a laugh! The vet assistant insisted I have to bring my chickens in for a $60 a piece exam before the vet would write me a prescription. She called the chickens "my pets". I was tempted to ask whether I can bring my pet cow along too.
So I took a little longer to think about why I am trusted to medicate my fish against a disease but am apparently too dumb to do that with a chicken. And do farmers walk their chickens to the office? No, they medicate themselves when needed.
So it finally dawned on me to just go to one of the feed stores in Delta and get the meds needed. As simple as that. I have just reminded myself how useful it is to stop and think:)