They could be a month old or 3 months, 6 months, a year.... No way to really know unless you have a hatch date, see an egg tooth or know how they were started (dry or wet).
Where did they come from? Maybe you can ask the source.
I've had humid started babies be larger at 3months old than dry started yearlings.
What Heather said is very true. The one at the top of the pic looks too already have some pyramiding started, which tells me they have been started dry. The best guess, and it's only a guess would be 2-4 months.
They're brand new. The one at the top of the picture is a bit older than the one at the bottom. The bottom one doesn't show any growth at all, so he's just hatched. The other one might be a couple weeks old.