Hi Tinaln I like to have my peahens raise peachicks too although this year I am not letting them do that.
Last year all of the chicks died. What happened was there was a lot of rain when the peachicks were little and while they would get under a shelter with their mom, the rain made them cold. I think all of the rain was too much for them and they couldn't find enough time to eat because they were busy shivering. I didn't realize they would die from all of the rain, but evidently from what my dad told me wild turkeys have a lot of chick deaths when it is a very wet year when the chicks are small.
Another issue I have found is if the peachicks can get through the fencing, I think the local hawks noticed this and ate ones that ventured out or something got them. It is good to have small fencing around the bottom of the fence so that the peachicks can't get out. My first peachicks never left the pen, but then the next time I had peahen raised peachicks they would venture out of the pen.
Once when I had peahen raised chicks, both peahens had several peachicks and in the end due to peachicks wandering out of the pen both peahens ended up having only one peachick each survive and the one that survived was normally the one that stuck very close to mom and didn't wander as much. For me I don't want to have peahens raise their own chicks again until there is smaller fencing and as for the rain I could probably put up a heat lamp or try something to keep them warm.
I have thought that maybe having an indoor area just for a peahen and her peachicks might be a good idea. That way they will all be safe and out of the elements and then when the peachicks are bigger and won't have issues with the rain you could let them out.