Hello Rrar,
I have also noticed the exact same thing.
Also, this was mentioned by another participant during my DAFNE course who said that eggs makes him spike!
I also have a spike from chicken and turkey.
When I called my doctor and asked him about it he came up with a hypothesis and he told me it may not be valid but, it is what he can come up with.
His hypothesis was, that if the chicken (or the eggs) is not free range then, the animals are fed with hormones and antibiotics in order to mature within 40-45 days (for consumption). My doctor's theory is that the hormones and the antibiotics, which exist in the end product, could theoretically affect our blood sugar.
Again, this is not a valid point, it is only his theory.
He told me to try free range and observe if I have the same results. (But, then again, I guess finding a actual "free range" might be someone difficult... I am a bit of consiparcy theorist and don't always believe the product labels...).