Here are a couple of posts with dosing for the ivermectin, the first also contains a link to another article on why it's not an effective wormer for poultry. Safeguard would still be a better choice. Also ivermectin can be toxic in too high of dose in poultry, so care should be taken not to give too much. Measure your dose, don't use drops, with drops it's too easy to either under dose or over dose. Safeguard (fenbendazole) is very safe in poultry.
If you had a yellow foamy dropping with small worms in it then it sounds like it's
probably cecal worms (a yellow, foamy dropping is likely a cecal dropping), but no one can tell you for sure without a fecal test.
If you use Safeguard you will do two doses 10 days apart. You can divide the flock into groups, by breed or color (what ever works for you) and do one group a day until you've gotten them all. You can also do a group and band them (inexpensive zip ties work), so you know who has been dosed, until you get them all. Then when you do the second dose, remove the zip ties as you dose, when they are all off, you know you got them all the second time.
I lock them in the coop at dark, go out early in the morning before the sun is up, take them off the roost one at a time and dose them, turn them into the run. When the coop is empty, I'm done. I do about 35 birds, takes me about an hour give or take. For birds that freak out or are hard to hold, wrap them in a bath towel like a burrito to hold their wings.
The pour on ivermectin dose is 0.1 ml per pound or 0.5 ml per five pounds.
The injectable ivermectin 0.05 ml per pound or 0.25 ml per five pounds.
However, as others have already said, it's not an effective poultry dewormer. Read this:
https://www.backyardchickens.com/threads/worming-studies-and-references.1053454/
There are also many threads and posts from people that have lost birds from worms after using ivermectin, so I choose not to use it for worms.
I use it for treating lice and scaley leg mites.
https://www.backyardchickens.com/threads/ivermectin-experiment.1114731/page-2
https://www.backyardchickens.com/th...l-dose-for-5-mg-per-ml.1606795/#post-27373594
