Centrachid do you ever have a problem with chicken lice or mites and how often does this happenIf your birds are in coop with covered run, then my only concern would be to make sure chickens sleep more than 6" away from any area owl can reach through with its feet. If chickens roost tight against owl can reach through either prevent that or make so owl can not see chickens. If birds free-ranged then getting them settled on roost a good 30 minutes before sun down and do not release them until sun up the following morning. This time of years owls will hunt during days that are overcast but they are not near the threat they pose at night. You do not disoriented or hungry birds out walking about when light levels are low. A good percentage of losses to owls I have dealt with appear to be the result of chickens not getting settled onto protective roost. The chickens having a lot of discord on roost needs to be corrected by adjusting roosting arrangements.