Dog fouling is a major concern to many people, not just because of the mess it causes, but because it can be a health risk. Dogs may deposit roundworm eggs (toxocara canis) in their faeces, which become infectious after about 3 weeks, and can remain so for up to 2 years. As the driver will make deliveries to many different properties throughout their shift, if the dog faeces were to get on any of the equipment it could cause cross contamination to any properties after, this is why drivers may fail a delivery for this.
If your delivery is unsuccessful due to an access issue, your supplier will often reattempt delivery within 5 days of your original on or before delivery date assuming the access restriction is resolved promptly. Please be aware some suppliers may charge a failed delivery fee to cover the cost of the failed delivery, and in some cases may even cancel your order and not reattempt delivery.