surprising behaviour

we have had 2 golden comets and 2 susssex whites for about 3 months now and they have become part of the menagerie.
unfortunately this week we have had to "dispatch" one of the golden comets as the breeder we got them from confirmed she was suffering from a peritinitus. we didnt want to let her suffer.
we now have a new golden comet who is getting used to her new surroundings.

what has surprised me is that the other original golden comet , (who we call "old longneck", because it really is very long!)  is normally very quiet but she has not stopped squarking and rosey since we had to remove her pal. she really seems quite distressed . over the past few days as the other old girl had been getting worse she had been sitting with her.  

i didnt realise that it would affect her the way it has as the 2 sussex dont seem to be bothered

is this normal for chickens to be aware ? or is it becasue they are from the same breed or same family

also dont forget upon the death of a hen or there removal the pecking order changes she just got promoted so shes showing her dominance.
alan