Does soy make eggs/yolks smaller?

[cameramaverick]

When we got our chickens we were using a soy-free feed. The egg yolks were huge! I thought it was the chicken breed. Got another breed laying, thought we lucked out again with a breed that made large yolks (I love yolks). Then my husband accidentally bought a feed with soy, and the eggs got smaller and the yolks smaller. Switched to a different soy free feed and everything is big again. Anyone else experience this?

 

[aart]

I'd look at all the ingredients, and especially the nutritional levels, of all the feeds concerned, compare them side by side.

Then factor in any other dietary supplementation (treats or any foods other than the bagged feeds) used during those times.

 

[Ridgerunner]

Do you still have the labels of the different feeds? What is the percent protein in them? Normally the higher the protein level the larger the eggs.

Have you changed anything else in the way you feed them? It’s not about the percentage protein in one bite, it’s about the total amount of protein they eat in a day. And that is spread over an average. One individual day doesn’t have that much effect, it’s an average amount of protein over several days. If you are feeding them different treats the amount of total protein may have changed. Or it may be something as simple as the arrival of winter if they were foraging for a good portion of their food. There are a lot fewer protein-rich creepy crawlies available now than there were a few weeks back for many of us. Plants have stopped making seeds too, which may be richer in protein than just grass.