Long chicken groan?

[AlexEve]

Hello
One of my 3 month old hens has started to make a really long groaning sound, which usually lasts between 5-10 seconds. She only does it around bedtime and when I’m holding her brother without her. Does anybody know why?

 

[oldhenlikesdogs]

It sounds an adult bedtime vocalization. Often when they are getting up on the roosts in the evening they will do some low humming like you describe. It probably has to do with telling everyone in the flock where they are, and finding out where everyone else is roosting. It made more sense when they slept in trees outside to vocalize as they settled in. That's my guess.