Everything will depend on carefully manufactured and monitored greenhouses, or even otherwise dark tunnels illuminated with LED grow-lights.
Which means that possibly at least one cargo launch to Mars will have a Boring tunnel machine aboard. It could be that "soil" a few meters down from the surface won't be as toxic.
In any case, greenhouses on Mars will be very carefully constructed and maintained, but they will be spread out as widely as possible for any number of good reasons. Maybe they'll simply be warehouses for hydroponics trays and stuff, or eventually raised beds for beans and tomatoes.
By then, after the harvest, the chickens may get turned loose to peck every morsel of greenery left like a flock of locusts.
And then the planting will start again.
Kudzickens, roaming Mars.
Unsupervised and uncontrolled.
It’s not science unless it’s mad science.