Kurdyuk

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As wikipedia puts it:

The weight of this part of a sheep's anatomy (for example, the sheep of the Hissar breed) may be up to 60 kg (130 lb).

Wikipedia also adds:

When being rendered, kurdyuk emits a strong odour, described as "acidy-poisonous". However, it has a rich flavor when ready to eat.

Update: This fantastic post on fat tailed sheep:

https://bogleech.tumblr.com/post/767264269961166848/arsanatomica-arsanatomica-dreamingdeeper