In general circumstances the chickens can easily peck a sitting pigeon to death.

WV points out the importance of the flock dynamics.
At one time,, I housed my 2 bantams and a blind EE together with my pigeon flock for the duration of winter. Rest of the chicken flock was in same loft area, but separated by wire screen. The regular chickens would have pecked to death my blind EE.
My pigeons, 2 Banties and Blind EE had no issues living together.
The rest of chicken flock had no access to do any harm.
Here are 2 pix from a long time ago. When I had my first pigeon, I kept my Serama with him for company. They stayed together in perfect harmony. Serama was a hen.
When I got more pigeons,,, Serama went back with the rest of my chickens.
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