Both Chester Zoo and Bristol Zoo are BALAI approved and both permit entry to assistance dogs. Bristol has a very detailed statement on its website explaining that it can only admit assistance dogs that are registered with certain organisations because all their "dogs adhere to the highest health, behaviour/training and welfare standards" and "It is essential that we are able to guarantee such standards, to fulfil our biosecurity regulations," It also explains that assistance dogs are not permitted in certain areas (e.g. walkthroughs) or where there presence is known to cause distress to the species on display.
Facilities at Bristol Zoo | Plan you Bristol Zoo visit online | Bristol Zoo
Facilities at Bristol Zoo | Plan you Bristol Zoo visit online | Bristol Zoo