Considering that worming chickens takes only a couple of days, probiotics should be given over the span of 3 days, starting immediately after the worming process is over. What type of probiotics are you using? Remember to throw away the eggs for 2 weeks after worming.

 

I actualy gave them a mix of save a chick, and a human pro-biotic about every other day for 2 weeks

The wormer appears to have worked great , no signs of stress in any of the birds

 

If you dust their feed with food grade diatomaceous earth, they probably won't get any worms to begin with. It's super cheap and goes a long way too. It has a LOT of uses around the homestead.

 

That - I use it for that purpose, and to dust down the chicken house in summer to keep down / kill all red spider mite.

I also add Verm-X to the feed a few days a month. It is a herbal thing and really helps to clear worms. You can still take the eggs whilst feeding it.

I dont use drugs for worming as I have never felt the need, but if I did, after finishing the course as prescribed I would give the birds natural yoghurt for 3 days. Long enough to help rebuild gut bacteria, cheaper than other stuff.