This is the Guinea Fowl forum not the Peafowl forum, but...
I know a lot of people raise chickens and Peafowl together with no issues, but... chickens can carry diseases that Peafowl are very susceptible to that can be picked up from soil the chickens have been pooping on, or even respiratory issues just from sharing a shelter, so you may want to raise them completely separate and not keep chickens in the same area where the Peas could be exposed to anything contagious/transmissible.