Actually it depends. I think they are worth more to the breeder who produce them than to resell them. Mostly cause the buyer will want a pair.
The problem is not when you have too many females, is when you have too many males or when they have proved and need to be replaced (by the double homo), hard to sell unfortunately.
Some double hets are worth more than others.
I am sure you wouldn't have problem to sell if they were het lavender and het axanthic, wouldn't you ?
If you can keep them, they are worth it. They can produce some amazing pied hypo eventually, and if you have a pied het hypo or hypo het pied, it's just get better at the odds.
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