oes here is a link to a possible solution for your sick chickies. We have had a number of people here in the state of Washington USA that have been having problems. I a bit much to post all here, but here is the link and I hope it helps some. https://www.backyardchickens.com/forum/viewtopic.php?pid=4801100#p4801100 you might want to check out pages before and after.
PS That is a wonderful picture of your son Danny and the baby Jessica.
PS That is a wonderful picture of your son Danny and the baby Jessica.