Female Ferrets Fighting

Question
I currently have 2 older ferrets.  My girl (Rascal) is 2 1/2 years old and my boy (Petey) is 2 years old.  When I introduced these two there was no conflicts or fighting.  They took to each other very well.  Now I introduced a new girl ferret (Darla) who we think is about 3-4 months old (the person we got her from could not tell us exactly)  At first all three were getting along well.  They were even all sleeping together on the bottom of the 3-tiered cage.  About 2 days ago I noticed my older female ferret (Rascal) fighting with the younger female ferret (Darla).  At first they would run around side by side and sniff each other.  Now the older ferret (Rascal) goes after the younger one (Darla).  Rascal will bite her neck and ears. Darla will hiss and scream. Rascal has dragged Darla a little but what concerns me is that Rascal literally scared the poop out of Darla twice.  I know that if this is dominance fighting not to separate them but now it seems a little more than just that.  My boy doesn't get involved  but hides.  All three sleep in the same 3-tired cage.  I put in new bedding on the bottom on the first night I introduced them.  My two older ferrets are now sleeping together in an ark type hammock but Darla sleeps by herself on the bottom.  They are all eating and drinking.  When I engage the 2 older ones in play they are their normal self.  Even Darla will play with me by dooking and jumping.  She is a little skidish about getting handled too.  I would like to know what I can do so the new ferret does not get the poop scared out of her anymore %26 will these 2 females get along?  Thank you for your help

Answer
It is possible they will learn to get along, especially since they did at first.  Darla may not have a lot of experience with how ferrets play and Rascal may be a bit rough for her liking.  It sounds like they just need some adjustment time.  If it does continue, Rascal is at the age where adrenal may be an issue, which means a trip to the vet.