As the last post says.... get rid of the feed and if possible the rats!
Rats are more dangerous to you and your family than the chooks.... about one in five rates carry weils disease and more than half carry the cryptosporidium bug..... so make sure you and your's wash their hands after being near the fedd, coop or birds, basically anywhere the little ratties can get!
Most importantly...get them trapped and excommunicated asap!! Or they'll breed like rabbits!?!?!