Bantam rooster and BIG girls

Can he REALLY mate with them and produce fertile eggs????

We have a mixture of chickens, some RIR, Speckled Sussex (all pullets) and then we have our Red Sex Links, EE's and 2 others that I have NO idea what they are. But this is the only rooster we have. We are trying to find a mate just for him, but not going so well.

I have been told different things by different people and wanted to ask here. Can this little rooster produce fertile eggs and if so, can and will those eggs hatch and will the babies be okay, like with no genetic issues????

We have a mallard duck that may have some kind of genetic issue, she is the same age as our other mallards but her eggs are still so tiny, no bigger than a golf ball and some are as round as a golf ball.

As @gryeyes said they can and do mate with others, though I have found that the fertility rate isn't as high as it is with the big boys ( we did think our rooster was shooting blanks but that was not the case) either way it shouldn't be a problem, and it is nice to see the 'under dog' or under roosters in this case still winning with some off spring. I have found that they seem to have more problems with the big puff balls ( Orpingtons, full sized Cochins etc etc) At one point I had 3 Silkie roosters all in together ( brothers that got along fine, though only one was meant to be a boy...) and they would team up to get the girls which I found amusing. one would climb up to a high point ( approx 40 cm) and them 'fly' down and land on its back to get it.

Some people who have fluffy bottomed chickens trim back the feathering ( if they aren't for showing) so that there is less fluff in the way. I always do this to my roosters at the start of breeding season anyways since I don't show.

So if this happens, will I need to worry about eggs sizes from the offspring girls or laying issues???

I have had 2 broody hens, but I have been discouraging them from sitting on any eggs because I was afraid of something weird happening. LOL

This is good to know. Thank you so much.

no there shouldn't be any problems. however a full sized rooster over bantys is never good idea if they are to big then they will crush the hens. if you do sit some eggs I would be interested to see some photos of how they turn out.