It can only be a lavender if each parent was either lavender or a split lavender. Do you know what color they were? So, depending on the parents, it could be a lavender.
It looks a lot like a silver gene. I am going to quote from The Genetics of Chicken Colour by Sigrid Van Dort and David Hancox:
"Silver is a sex linked dominant (dominant in one dose) gene and was discoered and described in 1912 by Sturtevant. It changes its gold counterpart (s+) into Silver, but has no effect on the Autosomal Red coloring of the shoulders and wingbow, back of the male; S is sex linked because hens have only one dose of it and roosters two. Silver is often used to improve the "white" in some breeds. Silver gives a super white, even cleaner than Dominant white.....Silver is also effective on chick down; it gives the down a greyish shade compared to the yellow of its golden counterpart. Take for example the white silkie. White silkies are mostly Gold (s+)and you can see this in the roosters who tend to have yellowish hackle and saddle feathers, especially as they grow older. By bringing Silver into the white silkies, a super white, whiter than the ordinary white silkies can be obtained. The difference in chick down between golden and silver birds can be used to sex chicks. If a golden rooster is paired to a silver hen, their offspring will be segregated into cream/buff femailes, and greyish blue males. The other way around....a silver rooster and a golden hen doesn't work because all the offspring will be greyish blue, having at least one S gene, so you can't determine the sex by the chick down colour. "
So to make a long story short, the greyish color of the chick down indicates the Silver gene base (S) instead of a gold (s+) base.