Q.Fruit blossom
I have 8 fruit trees .two pears apples plum cherry . Everyone is very healthy. They are approx 6/8 years old. This year they were all covered in tons of blossom but only a few ( about 10) on each tree converted to fruit. I have fed them and watered etc. We do have pigeons. Please help .

There can be several reasons for non bearing fruit trees. Pollination issues, environmental, pests, and disease.
You can start with a soil test, do determine if soil amendments are needed.
These articles will help you.
https://www.gardeningknowhow.com/edible/fruits/pear/no-pears-on-tree.htm
https://www.gardeningknowhow.com/edible/fruits/apples/no-fruit-on-apple-trees.htm
https://www.gardeningknowhow.com/edible/fruits/plum/plum-trees-not-fruiting.htm
https://www.gardeningknowhow.com/edible/fruits/cherry/cherry-tree-not-fruiting.htm