An animal house comprising: a tray unit; a latch coupled to the tray unit, the latch comprising a body that is attached to the tray unit, a first arm and a second arm extending from the body, the first arm and the second arm each being capable of independently flexing with respect to the body, the first arm and the second arm defining a fixed end (11, 21) proximate to the body, and a free end (13, 23) distal to the body, the latch further comprising a first wall provided on the first arm and a second wall provided on said second arm, said first and second walls (12, 22) extending from said first and second arms (10, 20), respectively, in a direction away from said arms (10, 20), the walls dividing the first and second arms (10, 20), and a restoring means, the restoring means being configured to restore the latch to a rest condition in which the first and second arms (10, 20) are substantially aligned with each other; and a panel defining an aperture bounded at an edge thereof by a first portion of the panel, wherein the tray unit is capable of being moved through the aperture from a closed position where the tray unit is within the animal house towards an open position, and the latch is arranged relative to the panel such that when the tray unit is in the closed position and the first and the second arms are in said rest position, the first and second arms (10, 20) are aligned with the aperture and the walls (12, 22) of the latch extend at least partially across the aperture and the first portion of the panel, the arrangement being such that the tray unit and latch may not be drawn through the aperture towards said open position without first applying pressure to the first and second arms (10, 20) so that the walls (12, 22) no longer extend across the aperture and first portion of the panel, but extend only across the aperture. a tray unit; a latch coupled to the tray unit, the latch comprising a body that is attached to the tray unit, a first arm and a second arm extending from the body, the first arm and the second arm each being capable of independently flexing with respect to the body, the first arm and the second arm defining a fixed end (11, 21) proximate to the body, and a free end (13, 23) distal to the body, the latch further comprising a first wall provided on the first arm and a second wall provided on said second arm, said first and second walls (12, 22) extending from said first and second arms (10, 20), respectively, in a direction away from said arms (10, 20), the walls dividing the first and second arms (10, 20), and a restoring means, the restoring means being configured to restore the latch to a rest condition in which the first and second arms (10, 20) are substantially aligned with each other; and a panel defining an aperture bounded at an edge thereof by a first portion of the panel, wherein the tray unit is capable of being moved through the aperture from a closed position where the tray unit is within the animal house towards an open position, and the latch is arranged relative to the panel such that when the tray unit is in the closed position and the first and the second arms are in said rest position, the first and second arms (10, 20) are aligned with the aperture and the walls (12, 22) of the latch extend at least partially across the aperture and the first portion of the panel, the arrangement being such that the tray unit and latch may not be drawn through the aperture towards said open position without first applying pressure to the first and second arms (10, 20) so that the walls (12, 22) no longer extend across the aperture and first portion of the panel, but extend only across the aperture.