Are kakan rajput also exist in bihar?

yes, kakan clan of rajput also exists in Bihar. There are 16 kakan dominated villages in old Shahabad district of Bihar and a few of them are - Ahpura, Dihra, Dullahpur, Labhuyani, Ankarua, Siyarua etc. Likwise, there are twelve villages in Darbhanga district and a dozen of villages in Balia, Azamgadh, Ghazipur district in UP.