I'm so glad for your happy news.
I really think it was poison of some sort, likely the rat. That will clear over a few days with severe convulsions. If it doesn't kill them, they will recover. Likely she'll lay just fine.
Every bird I've ever had with Marek's once it got to the point of unable to stand, with neck twisted back, died. So I really doubt this was Marek's. Possible, but doubtful. Plus Marek's is paralysis not convulsions.
So glad she didn't get enough of whatever to kill her. Canvas your property for the root cause so it doesn't happen again.
LofMc