what age are they? you really can't tell after the fact, as far as I know, you have to see them doing it... If they are older than 15 weeks, they are doing it... you will know for certain, here is a shot of one of my roos with my silkie/cochin mix...
oh, well then they are doing the deed, if you have roosters....and none have gone broody and hatched any little ones? Are you sure you have a rooster? Sorry if that is insulting...but surely you would have seen this happen by now?
Crack open your eggs and look for the bullseye on the yolk. Here's what to look for: https://www.backyardchickens.com/forum/viewtopic.php?id=16008
yes i have seen him doing it but only once or twice and when my chickens go broody they are never fertile apart from this year one was but i accidentley smashed it and last year another hen stood on it and all the rest just explode on the hens...
he may not be of producing age any longer...I am new to all this, I know there is someone else out there with the answer. Maybe you can post a new post with this exact question, how long a rooster is still productive...good luck, I will be eager to see the answer.