The cooks got into the hen house and ate all the chickens.
I think this phrase requires context.
The woman sounds like she has a terrible cold, and a potato stuck in her throat.
Why in this case the translation ' cooks eat chicken' is incorrect, while previously in the similar sentences such translation was accepted? Is this my mistake or program's?
At least in the southern US, "cooks eat chicken" means several cooks eat chicken derived from one or more chickens. "cooks eat chickens" means the cooks are eating more than one chicken. Chickens as a plural for chicken is quite common. The chickens all ran from the fox.
This is a course in Italian not, obviously, English. None of us would speak this way!
The animal, chicken, has the plural form "chickens."
For example: I have five chickens.
The food, chicken, is almost always used in the singular. To say "I ate chickens" would mean that you ate two or more birds.