Thanks, I wish I could keep her out. As soon as I graduate I’m taking my chickens and leaving but until then I can’t do much. Considering they all had a very small dose I’m holing they’ll be ok
I'm very sorry that you are in a bad situation
This sounds like a family matter - is there a way to come to a mutual agreement or do you have another family member or friend that would be willing to house your chickens until you can find a better solution. @sumi made a good point - it won't hurt to give them a flush. The vitamin K suggested by @Fairview01 would be helpful as well - hopefully they can tell you the dosage - you can find vitamin K at places like WalMart or CVS.
Here's a list of flushes http://www.backyardchickens.com/t/700526/flushes-for-aiding-in-toxin-removal

We had 1 dog that was poisoned and another one later that was beaten with our own baseball bat. Unfortunately we had no idea who did it either time. There's something wrong with these people.
Keep us posted, please.