new hens - why do they huddle together ?

hello my new 18 wk old lohmann pullets are really nice and healthy however when they are in their run the keep huddling together under the coop! If i in outside to them they come out to greet me however when i in back indoors they seem to all huddle together under the coop - why is this ? Is it because they are new and unsure or what ?

for comfort and safety after all as rachel said they don't know you or your place. Try tempting them with a treat or two and they will soon gain their confidence 

Hi Loole-Looe-Belle, they're in new surroundings, it takes time and they do come out to see you when your about, mine wouldn't come out the coop and they still go silent if a collard dove sings