I have a coop design under production however I am concerned about ventilation and locations of inlets and outlets, My coop design is for 3 chickens it is : 4 foot length 3 foot depth 3.5 foot height I live in the south uk and the weather is changing throughout the year, we rarely get snow but quite a fair bit of wind and rain and also hot summers. I do not want to have large gaping holes for the winter so will be having slide vents for as and when the tempreture is extremely hot, however my concern is mainly for the winter months which are harshly cold. what rough ventilation will I require for winter? should I have ventilation near the perches? should I have ventilation at one end and will that circulate the entire coop? Really confused and concerned I will do something wrong and I want the best for my chickens. Will appreciate help you have to offer.