There are 5 boxes of 10 chickens. It represents 5 tens. 5 tens represent the number 50. So, 5 baskets have 50 chickens.
In the given picture, there are 4 chickens outside the baskets. It represents 4 ones. Add 50 and 4.
50 + 4 = 54
In the morning, there are 54 chickens in all.