Maybe you could work out why they were getting separated from the peahen. Is the area set up in such a way to make it easy for them to become separated? She should call them and keep them with her but if there are too many barriers or spaces for them to get separated it might not be her fault. How old are they? Was she trying to look after them or ignoring them? Are there other peachicks still with her or was it just these two?
In my experience, peahens aren't great at counting so as long as they had most of their peachicks with them, they didn't go looking for stray ones. We changed some things and kept them in a smaller area until that was less of an issue.
I'm just wondering if the best thing would be to get them back to her and make some adjustments to their area so they can't go missing.