why can't everyone just get along!

hi everyone...thought someone might be able to give me some insite!
I have 3 cats - 2 male, 1 female all from the same litter. Age 2 years. In December, their other brother,Jake, died. He was the calm, laid back "leader" - not pushy , but we all knew he was "the man". Up emerges leader #2 (also male) - Bailey. They do all still get jealous of attention, but within the past 3 months they have started picking on Maddie, the female, for no reason! She's started to hiss at the them and growl at times. She has become rather distant and the other day I caught her swatting at one of the boys! She has been distant from me too unless it's just she and I. I think Jake used to protect her just by his presence- is that possible? ANy ideas as to whats going on with all of them? Both boys Bailey and Sophie(don't ask!) get along fine. I want everyone to get along, and I want Maddie to be happy! She is smaller than all the rest too and so cute.

ps. I never owned cats before and started out with 4!
Total learning experience!!!

Thanks you so much for your help!
kimberly

It sounds like they are competing for the top spot. If it continues, I would seclude the two boys in a room for several hours each day. Before you let them out, give them some Dr bachs rescue remedy. After doing this for ahwile, they may calm down a bit and have been able to have their own space long enough to keep some peace.