Chicken turned blue

Today i was watching my chooks and suddenly one turned blue as if she was choking, her head went all floppy and she appeared to be gasping for air and stumbling all over. I was so concerned that she was in pain i nearly dispatched her there and then but all of a sudden she regained her colour and re joined the flock.
I have noticed that she is a bit snuffley tonight.
last month she did have a lung worm and was treated by a vet, i found it strange as thery are treated every 4 weeks for worms.
Does anyone have any ideas of what might of happened today ?

Today i was watching my chooks and suddenly one turned blue as if she was choking, her head went all floppy and she appeared to be gasping for air and stumbling all over. I was so concerned that she was in pain i nearly dispatched her there and then but all of a sudden she regained her colour and re joined the flock.
I have noticed that she is a bit snuffley tonight.
last month she did have a lung worm and was treated by a vet, i found it strange as thery are treated every 4 weeks for worms.
Does anyone have any ideas of what might of happened today ?

Sounds like lung worm.  What do you worm them  with ?  If verm-x then that is not effective against lung worm IMHO and you need to use flubenvet.