If they are full grown sized, you can use 1 ml on the bird (you might use a bit less on the hen if she's still smallish). Put a couple drops on the skin at the crest feathers, half the rest on the skin between the shoulders, and the rest on the skin above the butt-fluff at the tail end.
You will also want to worm internally with fenbendazole or another wormer that is more broad-spectrum than the ivermectin. Safeguard liquid goat wormer (10%) can be given in bread treats or other food treats. (Do NOT try to dissolve it in their drinking water!!!). You can also give it orally if you are good at that sort of thing. Typically use 50 mg per kg -- divide the bird's weight in pounds by 2.2 to get kg. Typical doses are 2 ml to 3 ml for a male, depending on weight, and 1.5 to 2 ml for a female, again depending on her weight. Here's a great link (scroll down to post #8):
https://www.backyardchickens.com/t/926738/safeguard-and-feather-damage-while-molting
Since the birds are new to you, worm with fenbendazole (safeguard) for 5 days in a row, then wait 10 days and repeat the 5 day worming.
Congrats on your new peas, and welcome to the peafowl forum!
We're a pretty chatty group, and we LOVE pictures!
