A potential buyer from Ireland asked for details of postage costs for 6 hatching eggs to Southern Ireland. Whilst postage is not a problem I checked out the defra (food & farming law) guide on exporting. Here's a bit of homework, but you ought to get your own professional advice:
Taking a box of 6 hatching eggs as an example, there are legal obligations relating to animal health and paperwork/health attestation ought to be provided by an 'official veterinary surgeon' (ovs). Naturally, if you provide mainstream hatching eggs it is not viable to carry out all these additional costs.
I strongly advise you too seek professional advice if you are thinking of sending eggs outside GB and don't get caught out. It's easier to say you can't send to Ireland.
You may find this 'checklist' from defra's site which must be completed by an ovs and accompany consignments of under 20 hatching eggs for trade within the EU. Ebay does not permit a link here but check out defra website - check out poulty and egg section & then 'under 20' category.
Please let me know if you have a different understanding of the rules - thank you :0)