My female zebra finch appears to be making a coughing sort of noise now and then, she usually makes this noise after eating a bit of cuttlebone however it seems to just occur now and then more frequently. Could it be a cough, and if so what could i do to help her? She seems fine in herself, as active as she usually is, the male she lives with seems fine and has never made this coughing noise, and neither has their little baby (who is due to fledge tuesday

) she has been making this noise for about 2 weeks but is becoming frequent.
I'm sorry i can't describe it better than a coughing noise, i'm not sure how else to describe it, i know its not a beeping noise tho. Any help would be greatly appreciated =)