Introducing a single hen to a flock

Hi all,

At the beginning of this week I had four lovely girls - two Pekins and two Polish. Sadly one of our Polish was taken by a fox, leaving my kids utterly heartbroken as she was the favourite hen, very affectionate, handleable and adored by the kids. We’ve since reinforced security of the coop (to fortress status) and it’s crossed my mind that perhaps another hen may be called for for the following reasons -
- we originally only bought two hens (the Pekins) but chicken math was mathing and a year later decided to buy two more (the Polish). Integration was extremely smooth with no issues even though the two individual groups of hens were very bonded to each other.
BUT now the remaining Polish is noticeably and loudly pining for her lost buddy.

My questions are -
- how difficult would it be to introduce a single hen to our small flock? I’m aware that my Polish girl may not bond with another but she is obviously lonely. She also is annoyingly top of the pecking order.
- one of my Pekins is in a broody phase at the moment - she isn’t aggressive at all but I worry that introducing a new hen at the moment would disrupt things.

So should I wait until my Pekin is out of a broody phase and attempt an introduction? Should I leave things be for a while and reassess in a month or so? Would the suggestion be to add another Polish to the group or would another Pekin (or silkie or other bantam breed) be fine?

Unfortunately space is an issue otherwise I’d add another 4 and hope that my poor pining Polish would integrate well into a larger flock.

Thank you so much if you’ve made it this far, any advice or tips gratefully received!