Ponderosa rare breeds visitor centre and Lakeside restaurant has gone up for sale.
The farm and restaurant has gone on the market today for £1.3m with estate agent CBRE.
Mr Cook said he was selling the business so he could concentrate on expanding existing facilities for people with special needs and opening it out for people with mental health problems and elderly care.
He said they would be sold as going concerns and the animals and staff jobs would be safe.
He said: “We are going back to what we do best, which is working with people with learning difficulties. It is what we started with. We look after more than 70 people and we want to move forward with it.
“My sons have taken over my building business but they don’t want to carry on with the visitor centre and restaurant. I am 70 now and I have had cancer. The past six months have been a life check.
“All our existing bookings will be honoured and the business will operate at usual until a sale has been agreed. The attraction has such a huge and dedicated customer following and we are confident that it will further flourish under new ownership.”
Mr Cook said his plans included developing the Dewsbury Domes eco project, transforming the old Spen Valley Treatment Works off Walkley Lane into a state of the art educational centre; a care home for people with dementia, and developing land around the farm into an outdoor activity centre and allotments for the community.
He added: “By refinancing we can go on with what we want to do.”