Cecal worms are one of the most common worms in chickens, right behind round worms.
I agree Wazine is only effective against round worms, and the other poster was correct about Milbamycin from what I read.
Worms are ever present in chickens and their environment...which is why it is important to keep their litter clean and rotate their field as much as possible to prevent, as much as possible, worm build up in the soil.
You won't see worms unless there is an overload. It is important to prevent an overload as they can easily drain the bird's immune system and overall health, slowing laying substantially and allowing the bird to be susceptible to disease...and yes some, like cecal worms, can harbor nasty disease.
Fenbendazole is effective against a broad spectrum of worms in poultry. You would need to treat then treat again in 7 to 10 days to break the worm cycle of adults and eggs. If you use paste, it can be helpful to put it into a pocket of bread and feed each bird individually...raspberries are especially effective way of treating birds as they tend to gobble them up easily. Liquid form in the water is especially effective.
Be aware that fenbendazole is not FDA approved for laying hens in the USA (or UK). Vets can prescribe it off label, but technically, you would never be able to sell eggs from those birds, ever. If the eggs are for family use, no worries. If you sell them, you may need to consider if you desire to be within FDA approval.
Typically egg pull time is recommended at 10 to 14 days after last treatment.
Hygromycin B is FDA approved and is effective against round, cecal, and capillary worms in chickens. It is a feed based med (pellets applied to the feed). Industry offers it in continuous feed, but the company recommends feeding seasonally or monthly for 2 to 4 weeks. I have seen studies that recommend 6 weeks for cecal worms, however, I note much improvement after 2 weeks and worm 2 to 3 times a year.
Hygromycin B has no pull time for the eggs, per FDA regulation, as studies show it does not transfer to the eggs well.
If you choose Hygromycin B, you can get it too at the feed store in the form of Durvet Strike III or Rooster Booster Triple Action Multi Wormer. Rooster Booster also contains vitamins/minerals and probiotics which give the bird a nice boost as well.
In between worming, I like to support gut health and the immune system, the bird's first defense against worms, by adding Apple Cider Vinegar in the water (1 TB per gallon, raw, unfiltered, with mother, plastic containers only), and offering yogurt with pumpkin seeds and cayenne pepper and garlic. That helps the bird flush worms, but does not kill the worms so keeping clean litter is essential. That helps keep worm loads down between worming with meds, and helps reduce the need for meds.
LofMc