in process of intergrating 9, three month olds with older hens.

[bucky52]

i have had chicken wire seperating,the young chicks from the the hens for two months.this past sunday i decided it was time to merge them in togather.i don't worry about the hens hurting the young ones.as they were debeaked at the hatchery when i ordered them(.very shocked at that when i picked up the hens last year)my fear is the young ones will hurt themselves when the hens chase them.the young ones go into a panic.they scream and fly and run to hide in their coop.i am new to chickens,how long does it take for the hens to accept the new ones.