Cassiobury Farm and Fishery Open Days are running throughout the summer, the next is Saturday Thursday 8th August, with more on Saturday 17th August, Thursday 22nd August and Saturday 31st August.
You can either order on-line (by scrolling down to the day you wish to visit them on, by clicking on the following link) http://www.cassioburyfarm.co.uk/open-days-events/ or simply by purchasing tickets at the gate on the day.
They accept cash and credit cards on the gate. Prices are the same whether ordered on-line or at the gate, but there is a fast track entrance for those with on-line tickets so access is quicker.
Access to the Farm is on-foot only. The Cassiobury Park website gives the best information for parking and public transport. http://cassioburypark.info/directions-to-cassiobury-park/
There is on-site parking for blue-badge disabled drivers. No pre-booking is necessary. Access the Farm via Rousebarn Lane (use postcode WD3 3GD). No dogs, other than guide dogs, are allowed on-site.
You can leave and return during the day if you wish. Just ask the gate to stamp your hand.
Gates open at 10:00am. Last entry is 4:00pm and the Farm closes at 5:00pm.