Dyr is both the singular and plural form of the word, it has to be plural here because there's no article (one wouldn't say "Do you have animal?" in English).
According to Den Danske Ordbog, et husdyr is an animal that is kept or used by humans, for example, trækdyr (animals used for pulling vehicles) and kæledyr (pets) or to get milk, meat, wool etc.
Et kæledyr (lit. Cuddle animal), is an animal which is kept in the home to play with or to cuddle or for the sake of the hygge or companionship
Confusingly, the Dutch word "huisdier" means "pet". Damn you, Germanic languages!
'Do you have domestic animals?' is not very realistic english. It sounds bureaucratic
'Do you keep/have animals?' is what someone might really ask if they wanted to know if a family had e.g. chickens/pigs/horses.
The fact that they are 'had', 'kept' makes it clear they are not wild.
I don't think that's a mistake, Cambridge dictionary has 'domestic animal' as "an animal that is not wild and is kept as a pet or to produce food". The trouble is that a great many English speakers are not even aware of this usage, whereas I suspect 'husdyr' is quite commonplace.
thanks so much again and have a great weekend and I'll get it in time we will be able we have been in a meeting with the team on the road now but I'm going to try to go to sleep and I'm not sure how to do that and then we can talk about the details and the other two are having fun with your family or friends and we can get it in the morning and get back with you on that one but I'm not going to be