How much Relative humidity, was determined that in a level of 35 75% do not have interference in the initial development of chickens. The ventilation less has its studied effect, but it has stories of that exactly winds are not of great consequncias for birds with more than 2 weeks of age, thus, must be looked for to prevent regions where strong and cold winds with frequency occur, therefore this makes it difficult aeration of the installation inside, beyond demanding more solid and resistant constructions. The temperature is the ambient factor more studied, being object of many research, and has that the birds move of behavior to defend against high or low temperatures, thus, in the hot time has greater water consumption (with extreme consumption, the food remains little time in the intestine, and has minor time for absorption of nutrients, therefore the intestine must be healthful), whereas in the cold time the birds if agglomerate. In the majority of the works that compare different temperatures were demonstrated that for the 0 variable: weight profit, alimentary conversion, pigmentao and warping, the 25 temperatures of 15 C are adjusted, being the 15 results best that 25C, except alimentary conversion, therefore bird has greater nutricional requirement because it has that to produce heat, therefore we go to admit as ideal temperature for cut chickens the band understood between 15 – 25C, and inferior or superior temperatures to this band are of the zone of thermal comfort, and therefore they demand physiological adaptations in the direction to generate animal heat (when inferior) or to waste heat (when superior). Regions and/or periods exist where it has great diversity of climate, the times, even in an only day, and therefore it becomes difficult to plan the ideal environment, and what it becomes is to try to fight the element most harmful, that in our conditions is the heat, and to fight the cold, they are used measured of protection as:: heaters, curtain, mureta, etc. .