AbstractFemale chicks carrying a recessive lethal, sex‐linked gene designatedpx(paroxysm) develop seizures. In a population ofpxchicks (hemizygous females), the mean age of showing the first seizure is 19 days. The seizure syndrome can be generally divided into four phases: (1) alert phase (vocalization and/or running), (2) clonic phase (wing flapping, legs flex), (3) tonic phase (opisthotonos), and, (4) recovery phase. Seizures are spontaneous and recurrent but can also be precipitated by various environmental stimuli or by electrical stimulation of brain. Electroencephalogram recordings during seizures consistently show repetitive high amplitude spikes. Dilantin and sodium pentobarbital were effective in inhibiting electrically induced convulsions. No gross brain lesions were detected with light microscop