In 1.19 10 seeds do not instantly grow a chicken

I am trying to breed a lot of chickens, as it is commonly known every seed you feed a baby reduces 10% of the time it takes for it to grow into a adult. This would mean that after 10 seeds the chicken should grow instantly, however it doesn't. 

What I expected to happen was to see a fully grown chicken after I fed it 10 seeds or more.

What actually happened was the chicken didn't grow until some while later at the time of other chickens

Steps to Reproduce:
Breed two adult chickens

Give the baby 10 seed

Observe in disappointment