I have my own house, so pesticides and chemicals on the lawn are not an issue because I don't use them.
Risks from above were always a concern, there are a lot of predacious birds in my area, especially Red Tailed Hawks.
I always found my guys to be very sensitive to any temperature changes. I would take them out for short periods, and it always resulted in sneezing for days afterwards. I would only choose the perfect day, with temperatures in the mid 20's, and I did not have them in direct sunlight.
I don't do it anymore because of the sneezing afterwards.