How do you tell the difference

I'm not familiar with either, however, it is possible that they are, in fact, the same cross, but the different hatcheries call them different names.

The reason why I'm asking is I have 4 chickens, all supposedly Brown Shavers but 2 of them are slightly longer in the upper leg and broader across the top of the head, also larger combs. However they are 1 year older than the other 2, so am mystified whether they are different breed (Hyline) or the differences can be due to age. Oh, and their eggs are bigger.