Temperature dependent sex determination is a real thing but is believed to only occur in some reptiles and some types of fish.Probably. Just getting enough data is a massive problem.
It is of interest scientifically at the moment because of the likely implication of warming climate on sex ratio of those species.
Chickens like all other birds and mammals have genotype driven sex determination (sex chromosomes - X&Y in mammals and Z&G in birds) so I believe the incubator thing is nonsense unless it is some factor about survival of male vs female embryos which is biologically possible.
https://www.scientificamerican.com/article/experts-temperature-sex-determination-reptiles/
https://oceanservice.noaa.gov/facts/temperature-dependent.html
https://en.wikipedia.org/wiki/Temperature-dependent_sex_determination