If you use the pour on Ivermectin, I'd stick to using it on the back of the neck, where they can't reach it. If you even dilute the stuff and use it as a dip, I'd be concerned about them ingesting it. Even applied to the back of the neck, (If memory serves correct, it's only 4 drops/large fowl) it should work on the leg mites, b/c it's absorbed into the skin. (SCG, where are you! Her expertise should weigh in here as a final answer!)
Hahaha! I'm here but didn't want to weigh in. I have almost zero data on this!
However, if it were my birds I would do the following:
1. Treat with ivermectin pour on making sure to get it on bare skin for best absorption (sites are usually back of neck, under wings) using the following doses for a guide:
- 22 lbs = 1 ml = 20 drops
- 11 lbs = 0.5 ml = 10 drops
- 5.5 lbs = 0.25 ml = 5 drops
Most of my birds fall in the 5 to 8 drop per bird category. 2-3 drops per site is what I use. Repeat in 10 days and again in 10 days. I cannot find for sure what scaly leg mites feed on, if they don't feed on the blood then ivermectin pour on won't be effective.
Manna Pro has something called Poultry Protector, but looking at the ingredients and the directions for use, I personally wouldn't go for this. They also have a Scaly Leg Protector but the link on their website is bunked, so... can't tell. Considering it says "protects against" and "natural enzymes" I'm not apt to think it's going to help.
I would also
not soak the birds in anything containing alcohol or kerosene. That would burn.
2. Depending on the number of birds I had if it was feasible I'd also smear vaseline or bag balm on their legs and feet every other day for the first 10-20 days. I have 50 birds and a full time job...
3. Would do a complete coop clean out, spraying a permethrin based spray into all the cracks and crevices. Repeat in 10 days. Note that the scaly leg mite spends 100% of its life cycle on the bird, but creepy crawlies make me do this step.
Keep in mind that there is limited safety data on eating meat or eggs from ivermectin treated birds. I will tell you that I do it. You must decide for yourself what is right. I looked at whether this (or something similar) was used in humans, and looked at the toxicity data and possible side effects.