Yes.
It is really a matter of definition. At some point the ancestor of the chicken will not be enough chicken to be called a chicken. And this is kind of theory since these two creatures, the almost-chicken and the first chicken, will be almost identical.
You could say that it must have been a chicken-like creature that would be unable to produce fertile offspring with the species we today call 'chicken'.
But for every definition you try to make you will realise it would be impossible to pick out one individual egg and claim it was the first real chicken egg. Plus you can't go back and try it anyway so the whole question is kind of stupid. This is because evolution is so slow and subtle.