Here are some of the reasons why your chickens stop laying eggs, I know this is an old article but you may still find it useful.
https://www.thehappychickencoop.com/7-reasons-why-your-chickens-stopped-laying-eggs/
I used to be a member of this forum (https://forum.knittinghelp.com/). I have learned a lot of good knitting patterns from this community. I used to make baby shoes for my niece, below are some of my works. Also tried to make some dog shoes for my pug that he can wear during winter and summer...
How can I tell my uncle to slow down when driving? I feel like I'm going to die whenever I am his passenger. He doesn't even follow the rules that you have to stop and let civilians cross the street. I do drive, but there are times wherein I go on a ride with them to save gasoline.
Looking at the photo that you have attached I guess it is time to see your vet. She already had a bald spot on her chest which is not a good sign. Go seek for professional help to find out the reason why she is shedding on the specific spot.
It seems like the duck is badly hurt, here is what I have seen on the internet. I hope it helps.
Open wounds that do not require stitches:
Hold a clean piece of lintless cloth or gauze over the wound.
Trim feathers away from the edge of the wound.
Wash the wound with warm mildly soapy water...